There is a way!! There's also a catch, of course... I found a way, but you have to cheat. So far... It's the only way. I searched far and wide, and found to answer to this problem... But I researched cheat codes for the game to see if there was a way to walk through walls, or something... I found no cheat that posed any solution on paper. But I read there are some glitches with the restart level cheat, so I tried it out. If you enable cheats (-cheatenable in exe command line) and press F7 to restart level, and it will restart with the gas gone, door open and liquid standing outside!! I don't know if it effects your ranking at the end, but if you just want to play the damn game like I did, it lets you get through it! I wish I wasn't so lazy and just went out and bought a PS1!
Hope this works for you + everyone else who had this problem!