OK, you're the QB. You have moved off Pascal, pulled it back from T.Y. , ignored the checkdown to Mack. You're in a clean pocket and this is what you see as you continue to go through the progressions-
Where are you going with the ball?
The play broke down, it was defended. Like most QB's, time to make a play with his feet. I feel he wanted to sprint to the sideline and buy time for a receiver to get open. But Glowinski was in his way making him take a path closer to Chris Jones (who quickly disengaged from Kelly to pursue).
Castonzo lost his man shortly after JB7 tucked and started to bail. I don't think it would be long enough for these receivers to break away from their defenders- T.Y., Cain, or especially Ebron, on his butt in the end zone. Kelly wasn't in great position on Jones, as witnessed how fast he got to JB once he broke out.
Strip sack from the blind side would have been bad.
If I was talented enough to be in his shoes, I would have taken the safety valve to Mack and let him try to make a play. But I feel JB7 is every bit as talented as Big Ben to extend a play moving out of the pocket when necessary. So we don't see it the same. The WR are blanketed. I'm not sitting there forever in that case hoping a defender eventually falls down, instead of one of your targets.
I've made my case. (I think the check down to Mack). I'm moving on.