Problem with checkpoints

[Max504]

Ok I know there are a lot of threads about script problems but I searched and I couldn't find a solution to my problem. I'm fairly new to making maps in amnesia (just a couple of days) but I think I'm getting the hang of it.

In the custom story I'm making there is a part where you must run from a monster through a library, get into a room that locks when you enter (and the monster starts hitting the door) and then pass through a gate that is opened with a valve, the problem is that if the player gets killed in the chase he goes back to the checkpoint I placed before the start of the chase script but because the script already happened the monster doesn't appear again.

I wonder if there's some way to make the game load the last autosave instead of just teleporting the player back to the playerstart area. Thanks for your help.