I found out a somewhat reliable way to do the void glide used in @ZeroMaster010's Doom 2 12:44 TAS.
It's a little luck based since you need to shoot a barrel to a certain spot without it blowing up, but the spot isn't too precise. After you go through the first teleporter you need to face the wall at a certain angle so you shoot the barrel close to the wall and far left. Then (I had player coordinates on for help) face at the lowest possible 246 degree angle. I was using Crispy Doom and using -shorttics and I was only able to look at angles 244 and 246 no 245, so stay facing angle 246 while getting as close as possible to 244. Then backwards SR50 between the diagonal wall and the barrel.
Edit: I found that you want to face towards low angle 329, but not quite angle 327 when you shoot the barrel. -Shorttics skips over angle 328.
I couldn't figure out a set up to blast myself back in bounds yet.