So i spent few hours trying to squeez through but it seems for now its impossible. I managed to get to the top by jumping on npc head and riding it but as soon as you cross that barier and can see railing of the top floor nothing really happens and you cant get through elevator doors even if you already at the top. So even getting to the highest point will do no good because there might be no triggers. Also funny thing you can compleatly avoid fall damaga by fast save/load or by spining and pressing jump at the right timing just before landing but i'm not sure on exact mechanics with this.

I just happen to glitch myself on that golden hand and get into the elevator with npc but elevator will not let you go to the highest point you really do have to squish yourself through that ceiling.