[Black Plague] Final door sometimes opens, sometimes doesn't

[Laink]

Hello,

That thread will seem a bit strange to you, as I do want to do a glitch in the game, as I'm a speedrunner (I currently finish the game in approximately 15 minutes in one segment). There is something at the end of the game that I don't understand and I desperately need help from Penumbra BP's devs or community.

At the end of the run, the very last glitch is to clip through the wall in the Examination Room thanks to the shaft, to click the computer, click on the objects and finish the game by clicking again on the computer.

The problem is, when I click on the four 'objects' to trigger the computer, sometimes the door (2nd object) can't be clicked. And sometimes it can. It seems to be random.

It opens : [video=youtube]http://youtu.be/oBtTIt4gnXw[/video]
It doesn't : http://youtu.be/B6GKObG0axI

I did the two segments from the same save file, and tried to have approximately the same timing. In the second video, the door just can't be clicked, and I don't understand why.

Note : this glitch (when the door can't be clicked) happens a lot in single segment, when I do the game from the beginning to the end without loading a save. When I do load a save, it can be clicked most of the time (but sometimes it still can't be).

Note 2 : when I wait for the end of the dialogue before clicking on the computer for the first time, the door always opens, even in single segment.

I think it's random, but I can't help thinking this door behaves in a mysterious way I don't understand. Is this door deactivated by default and triggered by something ? Do I do something that deactivates it ? Is it just a random glitch ?

PS : Sorry for glitching the game, devs. This in an awesome game to speedrun. Here is my current personal best run if anyone is interested : http://www.twitch.tv/lainkompris/c/4207491 (WR is 15:23 by StriKe62700)
I got a 14:56 run, but it was cancelled by this door

Thanks for your help !