Fickle...
I admit I know nothing about BE 400 ops but I do know that TXKF poses a unique challenge: an ETP must be calculated at your turn around point over the airport. In the event of cabin pressure loss at the ETP, usually the most limiting factor in marginal types on flights of this sort, can you still make it back to MQI?
Also, with regards to your planning, MQI has no US Customs service so you would not be using that airport for any Int'l return flight.