I felt it was a bonehead play and he should have just grounded the ball, who cares? However, it could be the opposite. When he felt it closing in on him, he may have felt more vulnerable where he was and instinctively took off to get in the open and get down. Or he felt the pressure to make a play out of nothing because of Footsteps.
There is only one fact I know for certain. Given the time, he would have protected himself because as competitive as he is, he didn't want to give up his job unless Footsteps took it away from him as he did Bledsoe. Do we think he would have been fighting to get back in if that had been Cassel or Weeden out there? If you get the chance, take a good long look at his body language and eyes when Dak was wowing everyone. Not saying he's not happy for him and mentoring him but show me the QB that wants to go out that way. Think he doesn't know that after Weeden and Cassell everyone was antsy to get Romo back. You can take a look around this forum or any other and that's a reflection of how many were ready for the next franchise QB. Do we think he's not aware of that?
I posted something like these "why", "what was he thinking" posts but the more I think about that and him, I really do think he was feeling pressure to perform and quieten the DakAttackers. He's never been through anything like this before. No Cowboys team has ever seen this. He wasn't a husband, father or mentor on that play, he was the QB doing what they do.