I hope no one would risk the poor guy's life by wasting another 30 sec taxi (sic) off the runway instead of stopping asap and calling for a nurse/doctor - Just to save a bit of inconvenience? I hope not... If I was the Captain - or a friend or relative of his I wouldn't be thanking you for that, I can assure you.
How could an FO not have practiced this? It simply isn't possible to practice incap procedure if the FO can't stop the a/c!!!