wait, does that actually take you to the institute? or what? because if so then you skipped half of the game

Right now it does NOT. BUT, it is the exact same spot which does take you to the institute when you do the BoS questline. The spot above gets blasted open by that big robot and you jump down, loading you into the institute. That's why i thought it would be the optimal spot to get to the institute. So i just used the clipping method to get out of the map and go there, and the shaft you jump down is in fact there, just not an obvious loading trigger. Since testing is extremely hard on console, without cmd etc, i thought i'd share and maybe someone can do something with it :)

I tested it before, the loading zone isn't active before you do the BoS quest, I don't know what point it starts though, should be a way to clip in though.

Unfortunately I think you already need to get into the institute to activate that quest, there may be a way to sequence break though, of course

http://fallout.wikia.com/wiki/Ad_Victoriam

This is the quest that activates it. I believe the speedrun gets the railroad "nuclear option" though.

Seems useless, then. AFAIK the only thing that could currently sequence break the game harder would be early institute(without doing any quests).