It could have been much worse, so be happy it wasn't! Many years back, when one of the cats was still young (2-3 years old), we had a pet aquatic frog. We kept it in a locked tank with a dictionary on top.

We went on vacation for three days. When we came back, the cat had pushed off the dictionary and unlocked the tank, and gotten the frog out of the tank. We found the frog in front of the screen door, bitten and scratched to hell -- and still alive. We put it back in the water but it died shortly after. I was only nine or ten when that happened but it was still so sad!

If your kitten can squeeze under the door, what's stopping her from doing that again to get to the snakes? Be careful. :C