Hey everyone, having a question about an old pc game on DOS

[DreppMeister]

Ok so i have kinda a problem with the pc version of the game "Alien Trilogy" a 1996 game, i am stucked in the space jockey's ship (You will never hear me call them "the enginneers") so you remember on the second level of that part you have to walk on very slim corridors and not fall into the acid, BUT... As you know on those old Doom-likes you have that damn thing about the mouse that makes your character move when you move it, so i cant pass that level without dying because of this >:(. Someone knows a way to remove that? i make it run with DOSBOX emulator, thanks :)