A new night guard wasn't new, Bonnie was used to scarring them and often draining their power within their small office so he could kill said guard and stuff them in a spare suit

So when he hears there's a new guard, he's quick to make an apperance by the window of the office and there he taps against the window slowly to get the guards attention

"Oh security guard, open that metal door for me" he coos as his red eyes glow within the dark hallway