Gave it another go with your advice. I did notice the grates but I couldn't figure out the logic, but even with your advice it took me a few tries to figure out you had to walk back on the side of the grates, and I kept going forwards on the side of the grates. So I eventually did manage to make it past it :D The mechanic itself (or a similar version, at least) was also in Vampire the Masquerade: Bloodlines, and there it was a matter of choosing the right corridor when in the middle, but continuing on rather than going back.
Then the murderbot nearly murdered me, so I got out with 1 heart, and then in the final area one of those plates was wired in an unexpected way and it triggered a different fireball launcher and I got blasted :')
Had to restart from the beginning but I decided to give it one more shot, this time I did make it to level 3 and beat the game. I have to agree that level 3 is the best, it has a really nice atmosphere. The final area felt a bit tedious because it's so large and empty, and I had to collect 4 keys so it was a lot of walking back and forth when I saw yet another golden door behind each door.
I really missed strafing and walking backwards, especially in the later half of the game, but I respect the design decision as it would indeed make things a bit easier to avoid.