Yeah, I know I was lucky! It was a weaned / hopper mouse so I decided to take a risk. I wouldn't suggest that anyone do that. I also left a nice pile of lab nuggets in there for him plus an apple slice. The apple slice was partially eaten and the nuggets were untouched. I actually did get up in the middle of the night (three hours in) and checked on him. He was cowering in a corner. Three hours later (when I got up) I checked again and that is when I found him in the hide.
I for sure don't condone or recommend leaving an adult mouse or any rat with teeth in with a snake for any length of time. *edit: In fact I don't eschew feeding live prey at all if it can be avoided. I have had snakes (that were finicky with F/T) bitten hard by both adult mice and small rats. Luckily no major injuries, but some scarring occurred!
You are spot on dr del!