Pay attention. Stay in the room, watching the situation, with a pair of tongs or something to grab the mouse with if necessary to keep snake from harm. The mouse only stays in for a few minutes. In my experience if it has been more than 10 min snake is probably not interested. Then you remove it from the tank. A great majority of the horror pics you see of feeding issues the mouse/rat was just left in the enclosure and decided to chew on the snake.