I don't consider another school trying to hire a coach away to be an extenuating circumstance ... that is in fact exactly the event that, if the coach is successful, the university is trying to protect itself against, by having a buy-out clause in the contract.
Per the contract, CSU is owed $7.5m (or whatever) if McElwain jumps ship. And remember, the contract is a mutual agreement, so McElwain agreed years ago that was a fair value for the loss of his services / program momentum, etc. A university president who forgoes that amount of contractually owed money, just because Jeremy Foley flashes dimples at him, runs a strong risk of being unceremoniously booted at the next Board of Trustees meeting. Falls under the fiduciary responsibility expectation. Now he could use his discretionary powers to swap the $7.5m for something of nominally equivalent value, like $4m plus a home & away series, where part of the argument is that the added visibility from playing the Gators has significant value to CSU.
(Addon thought: The wording of the contract says that renegotiation of the buy-out has to happen BEFORE McElwain's (official) notice to the university that he is unilaterally terminating the contract.)