With the feeding response of my snakes, the mouse wouldn't get a chance to eat the kibble. Given the choice between the mouse eating kibble or eating the snake, I'd choose kibble. If your snake hasn't eaten him before he has a chance to hunker down and eat the kibble, he's not going to eat him anyway.
The pictures that you've seen of half eaten snakes are from a keeper leaving a rodent in the enclosure for DAYS at a time, not from a normal live feeding. The anti-live supporters often use them to sensationalize why you shouldn't feed live. A rodent being constricted isn't able to do the damage that is shown in those pictures while it's gasping to take a breath. That's more of an FYI - those pictures horrified me as well - until I was told the true story behind them. Well, it's still horrifying, but not a result of someone feeding their snake live, but rather as a result of irresponsible snake keeping.