Since the guarantor's obligation was part of an obligation subordinated to a second debt, the lender can't proceed against the guarantor until the second debt is retired and the subordinated obligation comes due. Under state law, the fact that the debt was subordinated by a contemporaneous instrument means that the subordination didn't count as a modification of the guaranteed obligation that would trigger the guarantor's obligation.
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.