[SCRIPT] Remove key after 3x uses

[Darkfire]

The only (as far as I know) difference between global and local variables is that local can be used only in one map, while global can be accessed in any map.
So, basically, each time a door is opened you need to add those scripts:
-one that adds +1 to the global variable
-one that checks if the variable is equal to 3/higher than 2 and if this condition is met, it removes the key
-and of course the one that opens the door.

I don't think it's necesseary, but you can set the variable to 0, preferably in the "global" file, using the OnGameStart function.