[1.3.3] Some bugs

#1
1) SCP-1499 breaks when trying to go there. The log is then spammed with the following:
"dimension1499" event ***************
ShowEntity: Entity does not exist
PositionEntity: Entity does not exist

and

"dimension1499" event ***************
HideEntity: Entity does not exist

SCP-966 was active when this happened

2) MAVs still happen - unknown why, often related to switching dimensions

3) Console spammed with "Fail to load sound: SFX/Music/The Dread.ogg" upon returning from heavy to light containment

I have noticed that a lot of errors seem to involve trying to load textures / sounds. Is there a way to cache them so that they don't have to be loaded each time they're needed? Alternatively, is there a way to error catch so that they don't break the game? It seems that the game tries to continuously load / assign things during each update loop, unless I'm mistaken - perhaps that's the only way to do things in blitz3d.

4) Reloading game after 1499 breaks with 966 active, and endless buzzing sound

5) SCP 966 sometimes moves super fast immediately killing the player

6) The stairs in the maintenance tunnel down to the small room where you get SCP-500 are super buggy. It's hard to climb back up after going down. In addition, going down the stairs seems to break the game's renderer in some situations, like when playing on multiple screens (laptop to a TV).

7) Sometimes, you can go inside an elevator and press the button to use it. This will then close the doors. If you press that button again, the elevator will say "calling the elevator." You won't move, and the doors will reopen with you where you were before. The elevator can then be used normally to take you to the floor above (this normally happens on the bottom elevator in areas like 049's event, the maintenance tunnels, etc)

8 ) Failed to load texture: GFX\npcs\body1.jpg while walking over the catwalk with gas in heavy containment