I installed the mac version of system shock 2 and I am currently in the body of the many. However, whenever I try to swim, I instantly died even though I am at full health. Can anybody please help me? Thanks.

well, the water in there is highly radioactive, but it shouldn't kill you instantly. make a quicksave right before the place, and share save_13 and save_14 (zip the folders, upload somewhere, post the link).