One other note - the RB was dead stopped until the tight end reached out, grabbed him, and pulled him towards the goal line. That is illegal and a penalty. You see linemen push piles all the time, but reaching out and grabbing a guy to pull/carry him across the goal line is still verboten.
Tough call, but I think the right one. Of course, with some better play calling, Tennessee should have won in regulation. On the last drive, Purdue was gassed, and Tennessee kept overthrowing bombs instead of just getting a couple of chunk plays on the ground and setting up a make-able field goal instead of a 56 yarder.