The reason it works is because of the jank vertical mouse movement that Unity has. Go into your key bindings and change move right to mouse right (up for some maps with glides), then just make your way there with the super jank mouse movement and use jank vmm to build momentum off the wall and you'll make the jump. Angle also matters, so if you keep failing, it's probably because your angle is off due to Unity being...Unity.

Simply put, don’t attempt it. Especially not in a full game setting.

If you are curious, however, the way I pulled it off was by bounding move-backwards to mouse_down, slowly moving your mouse back against the wall, and tapping d. After you get the wobble, you lower the lift, line the top of the chaingun with a specific megapixel on the wall, hold the A and D buttons, and wait for the lift to take you back up. After all this you’ll save about 15 seconds.

Once again, very complicated and unnecessary, I’d suggest keeping your distance from this trick.