Still haven't been able to replicate it tho, probably was a bug of sorts, but I have no idea how it got triggered. What I did was getting the key, going through the motions of progressing but then getting all the way back to the other Heisenberg door and picking up stuff along the way, killing whatever popped on the way down there/up back So, if its based on a trigger, it can be killing an specific enemy on that way down/up or triggering the audio log on the operation room Regardless, if thats the case, I don't know how faster it would be to backtrack and kill/trigger something instead of just fighting Strum tho

Hey! I've been busy with work so I couldn't try and get this video, but tomorrow/this week I'll try to mess with this again with some saves.

What i remember of this is: I triggered the Heisenberg audio and then backtracked all the way back to his radio and played that too (backtracked to get collectibles and stuff), and then walked up again to this and that was my thing. Don't know if I triggered another encounter in the way that skipped that or if the log was the one that did it, or if its just distance based, but again, I'll be messing some more with it again! You can also kinda hear Strum behind the wall still, not doing a thing and just waiting forever lol

(oh, and I did this in the normal difficulty, regular new game)

So, doing my run in the factory, I entered the room right before the Strum fight (The dude with the motor for a chest/head) after the Heisenberg talk and immediately back out to go find other stuff before progressing the story. Came back and Strum never popped out of the wall and the fight never happened, I just proceeded normally. Will try and re-do it from a save point later to try and get a video of it