Like sparlimb said...position coach. Who do you think is responsible for the organization, discipline, communication
of that happening. It's on the head coach. If he is a leader he is accountable for that. That instance is not why he should be fired. Winning and losing is a lot of little things. There were many occurrences that demonstrated Hoke has holes in organization, discipline, communication and if he can't get those right then he needs to make better decisions to cover his faults up and he was even worse at that all day too.
And if he knows the personality of QB#3, as a coach paying attention would, then ya he had plays prior to the helmet coming off. They were taking dang near a minute off the clock each play...it wouldn't be unheard of to tell his manager to go get him #3 QB to stand next to him and to mentally prepare him to focus. Good coaching is coaching a few plays ahead. You anticipate things. You prepare for things that might or might not happen...but you think about it in advance. People next up is pretty basic.