Invalidity of Loan Documents. Any Loan Document, at any time after its execution and delivery and for any reason other than as expressly permitted hereunder or satisfaction in full of all the Obligations, ceases to be in full force and effect with respect to any Loan Party; or any Loan Party other than the Administrative Agent or one of the Lenders contests in any manner the validity or enforceability of any Loan Document; or any Loan Party denies that it has any or further liability or obligation under any Loan Document, or purports to revoke, terminate or rescind any Loan Document; or