I don't feed live, but if I had to I would sit and watch the snake the whole time. I have too much invested in my pythons to let a couple dollar rat do tons of damage.
Next time you could try stunning the rat? Put it in a plastic bag and give it a good conk on the floor (make sure your bag is sturdy)...it'll still be twitching pretty good for BP when you put it in the enclosure.
JonV