If Irvin tries to drive when he catches the ball, I think you end up with a step back jumper from the elbow. Maybe that goes in, maybe not.
This was the time to drive and get down hill IMO and MAAR seemed to kind of be hesitating to go anywhere. Maybe the best case scenario is MAAR sprints the ball up the court and you call a timeout with 8 seconds left and run something.
I don't really see the swing to Duncan in the corner as an option when Irvin catches it, McIntosh is already on him. The difference between that and the Chatrman shot is that Chatman's defender was in helpside for the pick and roll which drew him in.
It's not the shot anyone would have drawn up, but you are gambling a bit by going unsettled in a spot like this. I'm generally okay with that gamble, but wish Walton had the ball in his hands rather than 20 feet behind the play.