Since I know it's likely to be puzzling: at 32:09 I throw a gas grenade despite having already killed the scientist, because the grenade glitch defaults to standard grenades *until* you've used a gas grenade in that level. I was thrown off by an extra guard spawning near the test subject and wanted to do my usual strats rather than improvise, which didn't work out very well, as I missed the grenade glitch setup anyway.
On the approach to this fuel tank, I look to see if Gabrek is approaching the corner, as he can be aggro'd by hearing enemy gunshots or seeing you as you come down the corridor. If that happens, it's very hard to kill him while also dodging the enemy wave that spawns nearby. So as soon as I tag the fuel tank, the game checkpoints me and I go into the menu and load to the nearest checkpoint, which I just hit. It costs about 5 seconds, but it resets the guard positions and I can take Gabrek out without being shot by the very difficult guards in this level.
@@Baronhaynesthanks for the quick reply! You explained it very well. I haven't played this game since the early 2000s so I forgot about being able to load checkpoints. It all makes sense now.
Gabe and Lian have a long dialogue during the level fadeout, which you can skip by killing Mara, triggering Lian's "We needed her alive" line. The level still completes, and it's a few seconds faster since you don't have to wait for the regular dialogue to finish.