He took himself out on a 3rd down. Pretty baffling.
I've never heard of a QB doing that before. It is odd that he even thought that was an option. How does that thought even enter his mind?
Yeah, after they run three go routes in a row, or crash their body through an NFL defensive line a bunch of times or break a long run. It isn't the same. What he did was nowhere near as physically taxing as what skill position players do before rotating out. And they do it because the position demands running full speed all the time, which QB does not.