Trust Account Waiver. Notwithstanding anything else in this Agreement, the Stockholder acknowledges that it has read BRPA’s final prospectus dated November 20, 2017 and understands that BRPA has established the Trust Fund for the benefit of BRPA’s public shareholders and that BRPA may disburse monies from the Trust Fund only # to BRPA’s public shareholders in the event they elect to convert their shares into cash in accordance with BRPA’s Charter Documents and/or the liquidation of BRPA or # to BRPA after, or concurrently with, or in connection with the consummation of a Business Combination. The Stockholder further acknowledges that, if the Merger, or, upon termination of this Agreement, another Business Combination, is not consummated by December 23, 2020, or such later date as shall be set forth in an amendment to BRPA’s Amended and Restated Certificate of Incorporation for the purpose of extending the date by which BRPA must complete a Business Combination, BRPA will be obligated to return to its shareholders the amounts being held in the Trust Fund. Accordingly, the Stockholder, for itself and its [stockholders, directors, officers, employees,]13 Representatives[, Subsidiaries]14 and Affiliates, hereby waives all rights, title, interest or claim of any kind against BRPA to collect from the Trust Fund any monies that may be owed to them by BRPA for any reason whatsoever, including but not limited to a breach of this Agreement by BRPA or any negotiations, agreements or understandings with BRPA (whether in the past, present or future), and will not seek recourse against the Trust Fund at any time for any reason whatsoever; provided that nothing herein shall amend, limit, alter, change, supersede or otherwise modify the right of the Stockholder to bring any action or actions for specific performance, injunctive and/or other equitable relief (including, without limitation, the right to compel specific performance by BRPA and Merger Sub of their respective obligations under this Agreement). This paragraph will survive this Agreement and will not expire and will not be altered in any way without the express written consent of BRPA.

Simultaneously with the occurrence of Completion of the Project, ​ shall enter into a Cash Management Agreement with a Cash Management Bank. ​ acknowledges and agrees that the Cash Management Agreement shall provide, among other things, that upon the commencement of the first Trigger Period (if any) hereunder, a cash collateral account shall be established at the Cash Management Bank (such account, the “Cash Management Account”) in accordance with the terms of the Cash Management Agreement. ​ hereby grants to ​ a first priority security interest in the Cash Management Account and all deposits at any time contained therein and the proceeds thereof and will take all actions necessary to maintain in favor of ​ a perfected first priority security interest. ​ hereby agrees that the Cash Management Agreement shall constitute an account control agreement with Cash Management Bank for the purposes of the UCC, and authorizes ​ to file ​ Financing Statements and continuations thereof to perfect ​’s security interest in the Cash Management Account if reasonably necessary. ​ and ​ shall have the sole right to make withdrawals from the Cash Management Account, and neither ​ or any other Person claiming on behalf of or through ​ shall have any right or authority, whether express or implied, to make use of, or withdraw any funds, investments or other properties from, the Cash Management Account, or to give any instructions with respect to the Cash Management Account. All costs and expenses for establishing and maintaining the Cash Management Account shall be paid by ​ from time to time in accordance with the Cash Management Agreement. The Cash Management Account shall be assigned the federal tax identification number of the ​. ​ shall provide ​ or Cash Management Bank, at any time upon request of ​, with a Form W-8 or W-9 to evidence that ​ is not subject to any back-up withholding under the IRS Code. If ​ has not completed the process of opening the Cash Management Account with the Cash Management Bank prior to the first Payment Date during a Trigger Period, then

Voluntary Contribution Account. In the event that less than one hundred percent (100%) of a Participant's interest in the Plan is distributed to such Participant's Spouse, the portion of the distribution attributable to the Participant's Voluntary Contribution Account shall be in the same proportion that the Participant's Voluntary Contribution Account bears to the Participant's total intere st in the

[[Organization B:Organization]] shall maintain, in accordance with its customary procedures, a loan account ("[[Organization A:Organization]]' Account") in the name of [[Organization A:Organization]] in which shall be recorded the date and amount of each Advance made by [[Organization B:Organization]] and the date and amount of each payment in respect thereof; provided, however, the failure by [[Organization B:Organization]] to record the date and amount of any Advance shall not adversely affect [[Organization B:Organization]] or any [[Organization C:Organization]]. Each month, [[Organization B:Organization]] shall send to Borrowing [[Organization B:Organization]] a statement showing the accounting for the Advances made, payments made or credited in respect thereof, and other transactions between [[Organization B:Organization]] and [[Organization A:Organization]] during such month. The monthly statements shall be deemed correct and binding upon [[Organization A:Organization]] in the absence of manifest error and shall constitute an account stated between Lenders and [[Organization A:Organization]] unless [[Organization B:Organization]] receives a written statement of [[Organization A:Organization]]' specific exceptions thereto within thirty (30) days after such statement is received by Borrowing [[Organization B:Organization]]. The records of [[Organization B:Organization]] with respect to the loan account shall be conclusive evidence absent manifest error of the amounts of Advances and other charges thereto and of payments applicable thereto.

Primary Concentration Account. Commencing with the date that is six months after the Effective Date (or such longer period as Lender may agree in its discretion), Borrower will maintain its Primary Concentration Account with Lender.

Deferred Compensation Account. Interest shall be credited on the balance of each participating Director’s Deferred Compensation Account commencing with the date as of which any amount is credited to the Deferred Compensation Account and continuing up to the last day of the quarter preceding the month in which payment of the amounts deferred pursuant to the Plan is made. Such interest shall become a part of the Deferred Compensation Account and shall be paid at the same time or times as the balance of the Deferred Compensation Account. For periods prior to July 1, 2008, such interest for each calendar quarter during the deferral period shall be computed at seventy percent (70%) of the higher of the following averages: # the prime rate charged by the major commercial banks as of the first business day of each calendar month (as reported in an official publication of the Federal Reserve System), or # the average monthly long-term rate of A rated corporate bonds (as published in Moody’s Bond Record). For periods on and after July 1, 2008, interest shall be credited at one-hundred twenty percent (120%) of the long-term applicable federal rate, with quarterly compounding, as published under Section 1274(d) of the Code for the first month of the calendar quarter.

BioThrax Receivables Account. Maintain the BioThrax Receivables Account with # a Lender or # another depository bank that is not a Lender, subject to a customary Account Control Agreement in favor of the Administrative Agent.

NuThrax Receivables Account. Once NuThrax has obtained either # full FDA approval or # FDA emergency use authorization pursuant to [Section 564] of the FFDCA, maintain each NuThrax

Stock Unit Account. In the case of cash deferrals, the account will be credited with the number of shares of Common Stock that the amount deferred could have purchased at the Fair Market Value on the date the Non-Employee Director’s cash compensation is payable. In the case of a credit to the Stock Unit Account in lieu of the grant of Restricted Stock described in Section 4(a) or 4(d), the account will be credited with the number of shares of Common Stock otherwise applicable to the grant of Restricted Stock subject to the same vesting conditions otherwise applicable to such Restricted Stock. Thereafter, any dividends earned will be treated as if those dividends had been invested in additional shares of Common Stock at the Fair Market Value on the date the dividend is payable. Vested amounts credited to the Stock Unit Account shall be distributed in shares of Common Stock either in a single payment or in substantially equal annual installments (over a period not to exceed 15 years), as specified by the Non-Employee Director on the deferral election form. Any fractional shares will be paid in cash. If a Non-Employee Director fails to specify the manner in which the Stock Unit Account shall be distributed, then it shall be distributed in a single payment.

Distribution of Account. The Company shall distribute amounts from the Participant’s Deferred Compensation Account and the Deferred Stock Account in the manner and on the date(s) applicable under this Section 6. If the payment option described in [Section 6(a)(i)] hereof is applicable, the amount of the lump sum shall be calculated using the valuation of the applicable portion of the Participant’s Account as of the December 31 preceding the date of the payment. If the payment option described in [Section 6(a)(ii)] hereof is applicable, the amount of each installment shall be calculated using the valuation of the applicable portion of the Participant’s Account as of the December 31 preceding the date of the installment payment divided by the number of installment payments that have not yet been made.