I for one don't think Critchlow beat him out with that game. I think Joe did a fine job with a extremely dumbed down offense against a team we usually destroy. Also helping the situation is that the rest of the offense is starting to click. The last few games the line has really improved and is doing great opening running lanes which keeps the defense honest. The receivers as a group have also matured.
Like I stated Critchlow did a fine job but he stared down his receivers and rarely checked down. This was by design as Ty wanted to keep things simple for him. Mangum has a much more firm handle on what Ty wants to do and was steadily improving in that regard. This is especially true of the mental part of the game. If the other QB's want to beat out Mangum they are going to have to play catchup in the spring and demonstrate that they can equal or beat Tanner in the mental aspect of the offense..