The photos you see of really messed up snakes, the rat was in there a while. You can reduce the possibly of damage just be being there and being observant, do not leave a live rat unsupervised and be aware of what a nervous rat looks like and you are well on your way to preventing damage to your snake. Make sure the rat is well fed and have a pencil or something similar to block or put in their mouth after they get stuck and you are about as safe as you can be. You will learn pretty quick what a nervous or curious rat looks like, then you can bonk them as needed, usually works for me.