End of half is pretty risky. End of game doesn't matter a ton if you leave a few seconds on the clock. Whether game ends or not, most coaches rather take the safety and kickoff.What's the longest amount of time that can be left on the clock at the end of a half/the game that would allow a player to run around in the backfield and let time expire?
I remember MTSU did that once in their own end zone on 4th down and they managed to kill 8-10 seconds off the clock to end the game without having to punt back to the opponent.