You don't have to worry about bites, it's very common for beginner live feeders to feel worried about the bites of a mouse or rat.

Most of the 'deadly rat bites' are from an irresponsible herp owner leaving the rat or the mouse in the cage for too long of a period of time, which IS dangerous.

Many people feed live with tongs, which is easier because you don't have to wait and watch for the snake to eat, it has already started eating as soon as you close the tub.
As long as you don't leave the mouse or rat in overnight and you keep an eye on the feeding, there should never be a problem. Even if there is a little bite, it's probably not going to be harmful or dangerous to the snake.

If it helps, my only live feeding corn snake has been bitten several times and I've only had him for a short amount of time, none of the bites have been findable within the next day.

However, if your set on trying to feed PK there are two humane ways that I see fit. Some people will also say smacking it on a hard surface is good, but it can be messy and if not done right, not very humane.
First off theres the best method. Slow CO2 Gas chamber. You can get a plain old cooler and put some dry ice (in a separate air flow container like a critter keeper) and put the mice or rats in. Do not add water to the dry ice or let the dry ice sit by itself before adding the animals! This creates a much more painful death. When the CO2 is administered slowly, they fall asleep and die.
Secondly there is CD. Which is dislocation of the main vertebrae behind the base of the skull. Using a spoon or any piece of metal you securely hold it behind the skull and pull sharply up on the tail in which you should hear or feel a dislocation and it should be over. This also can be done wrong, so be careful here.

Good luck!