While running the Any% Full Game category, I discovered a skip in the mission "Kreisler's Garden." In the hydroponics lab towards the end of the level, there is a gate with an interactive panel. It's required that you interact with the panel to open the gate, which leads to a small room with a computer terminal that you must access as part of the mission. After interacting with the panel, it is revealed that Gabe doesn't have access to it, and asks Teresa to hack it. She'll then tell you that she needs some time, forcing you to clear the lab of enemies. Once the last enemy has been killed, the gate will open. Every once in a while, however, the gate will open immediately after interacting with the panel, skipping the need to kill the enemies in the lab. I call this the "Teresa Skip."

I'm not entirely sure what triggers the skip to occur. I would encounter the skip once every ten or so runs, and thought that it was just random. After doing some experimenting with the level, though, I realized something that had never occurred to me before. In some levels, the enemy spawns are tied to enemies that spawn before them. For instance, in the L-shaped hallway prior to the hydroponics lab, there are two regular enemies, and a flamethrower enemy that spawn. If you don't kill the two regular enemies, the enemies within the lab won't all spawn in. This can result in a sort of softlock. Since the enemies haven't all spawned in, Teresa won't open the gate. To remedy this, you'd have to go back to the hallway, kill the two enemies, then return to the lab and kill the enemies that spawn in. However, not all enemies are tied to spawns later in the level. Some enemies seem to be tied to event triggers, as well. Of course, there are the obvious ones. Such as Red Jack, who triggers the end of the level "Red Jack" when killed. There are also enemies tied to event triggers that aren't as obvious. From my experimentation, it would seem that the flamethrower enemy in the L-shaped hallway is somehow tied to the panel that opens the gate in the lab. By not killing that specific enemy, the gate will open without the need to kill all of the enemies within the lab. Or in other words, the Teresa Skip will occur. However, the skip won't happen every time. For some reason, every few runs of the level, the skip just wouldn't happen. Despite me leaving the flamethrower enemy alive. I haven't found an answer to why the skip works some times and not others. But for now, the skip is worth it when it does occur, and helps save around 5-8 seconds depending on your skill dispatching the final wave of enemies .

Nice find, never happen that in all the time I played Dark Mirror

I know of a couple others I plan to make threads for in the future.

UPDATE: So this trick is consistent. However, I was wrong about the timing of the skip. Instead of the door opening automatically, there will be only ONE enemy that spawns in the lab, then the door opens. So if you leave the flamethrower guy alive, you'll only have to kill one dude in the lab (he comes down off a zipline) instead of the normal four or five before the gate opens.

I'm currently working on Kreisler's Garden runs rn. This skip will be showcased when I post a run to the leaderboard.

I actually got a variation of this glitch, even if the door don't open ASAP you start the scanning of the hand. I was on PS2, then that glitch wasn't fixed

Nice. Makes me wonder what other things like that we can find.