Darwin's lifting-harness includes a pulley-unit, yet as he is lowered into the tank, the pulley is gone.
Lloyd Bochner's character is constantly referred to as Ivan Karp, although in the opening credits, his name is listed as Ivan Kard.
Tear gas does not have an anesthetic effect; it would not merely make Jaime limp and groggy, but would instead produce severe burning in Jaime's eyes, even if she weren't breathing any of it in.
Jaime doesn't pull the lifting-cable anywhere near enough to raise the test subject out of the tank, especially since the lifting apparatus uses a compound pulley system that would require the cable to be wound in many times farther than the subject was raised.
Rudy tells Jaime to listen for a heartbeat, but the sound that is heard is the medium-pitched electronic tone of an EKG beep, not a deep-toned throb of a human heartbeat. The idea was that the man's heartbeat was so faint that the EKG unit could not detect it, but Jaime's bionic ear could hear it. So the sound that Jaime should have heard was a regular heartbeat pulse, not an EKG beep.
Darwin is merely being swung over the water-filled tank, and so the winch-cable would not need to still be reeling in to raise him up any higher.
Relaxing would not stop a heartbeat, yet when Darwin is willing himself to relax, the EKG display shows him being flat lined between widely-spaced random irregular heartbeats.
In the scene where Darwin starts to mentally prepare himself to rescue Jaime from the tear gas, a good-sized scratch in the film stays in-frame for a second, obviously showing that the film was paused at that frame for a moment.
Darwin is back to normal and awake, yet when he reaches his hand up to feel the electrical field from the EKG unit, the screen shows him as still flat-lined.