SORRY ITS NOT A CLIP ITS A TRICK, YHET PUNCHES THE STREETCLEANER INTO THE CLOSED DOOR, AND WHEN THEY GOES BACK IN, THE DOOR IS OPEN????
yeah, you gotta punch the sc one that little rectangle area right above the door
For some reason enemies can open doors in wrath (its easiest to see this in the start of 5-3). when you load checkpoint the locks are taken off of the doors so they can open again but this happens before the enemies are reset so the streetcleaner is able to open the door and is then removed leaving the door open.
The easiest way to do this trick is just to jump on top of the door and wait for the street cleaner to come over before reloading. I would recommend doing that if you are having trouble punching it over as that method doesn't save that much time.
If you have not seen ULTRAKILL is finally having a speedrunner competition for real money!!! It starts in about four hours from the time I am making this news post, in fact its probably already started when you are reading this so click the challenges widget on the right and read up on the rules and