This could have been a real problem if inadvertently departing rwy 23 put him face to face with traffic arriving on 5. Tower controllers will routinely do a waiting pilot a favor and permit a "no delay" departure ahead of an arriving aircraft.
Additionally, since he was departing from an intersection, there could have also been a problem with remaining runway length. Hopefully he will never make that mistake again, for the sake of his passengers and the neighbors who live near the Buffalo Airport.