So I've found this new bug and been sitting on it for a while since I keep forgetting to actually make a tutorial but eitherway, here goes.

• Video Here in case you want a TL;DR
• As far as I know, this only works on the "Institute" level, at least this is the only level that it seems to be the best place to use it in.
• You need to grab the large square-ish wooden box (found after picking up the pickaxe in the level)
• When grabbed, set yourself up for a prop fly (E+Left-Click) and head towards the gate that is on the opposite side of the way that you're supposed to go (towards brent and the chemical collecting)
• Make sure to be facing the actual doorway you're supposed to go through when lining up for the trick
• You're going to want to bring the crate towards your character as you hold your backwards movement button (Default: S)
• Look up and as you look down, spam your "Rotate Object" keybind (Default: R) in an almost swing like fashion.
• If done correctly you should just clip through the wall onto the other side, near the end of the level, all that's needed after that is a prop fly up to the appropriate side and continue through, saving around 1m 30s roughly

Notes:

I am pretty sure this may only work if you have your rotate object keybind on your scroll wheel like I do

Also it's very tempermental, but if you can pull it off in a run then it can save a fair amount.