You're not understanding the concept of the play. Davis isn't double covered, he's supposed to split the zones of the CB and the safety. That's the whole point of the high/low post corner. In fact this play is exactly what everybody wants Allen to do - read the defense pre-snap, confirm the coverage post-snap, get the ball out right away based on the read. But none of that matters if the read is taken away by a lousy route concept and lousy execution.
The issue is that Davis didn't necessarily cut too soon. Based on the other two examples Kurt Warner showed that is for some reason how Dorsey wants that concept run. It doesn't make any sense.
Allen is literally just following the concept of the play. Isn't that what everyone wants? If he messed anything up it's the ball placement but like Warner pointed out he is rushing the throw because of when Davis breaks.
Allen made a lot of mistakes in this game. This wasn't one of them.