This one's weird, because he was given very clear instructions that he disobeyed.
But ultimately it's a bizarre rule, and if they weren't going to let him use it while docked and were going to keep the plane there for that long without taking off anyway, they should've given him another option rather than just "hold it until we say so"
And obviously, if they're stuck on the tarmac, no one can exit the plane. Sounds like their policy in this situation was "hold it until we say so or until you piss/crap yourself."