Revealing mistake: Near the beginning, when the car is lowered into the underground complex, the car is sitting on a section of the street pavement above. When shown underground, it's sitting on a rug or carpet that appears as if it were supposed to represent a dirt surface. There are even visible tire tracks. (00:07:20)
Revealing mistake: During the miniaturization process after Phase I, the sub has been reduced to coin-size at best. As the techs are beginning Phase II, they roll wheeled equipment by the tiny sub. There is a close-up of the sub pilot looking eye-level with the equipment wheel axle, and a tech's ankle is slightly below the pilot's eye-level. This is an impossible perspective: for the pilot to be eye-level with the wheel axle, the sub would have to be more like a foot in diameter and not coin-size. (00:27:10)
Revealing mistake: It's painfully apparent that the actors are hung on wires pretending to swim while outside the sub.
Revealing mistake: Near the beginning of the movie, Grant is in the car being lowered but the shadow the car makes remains the same.
Answer: I think the countdown began after the crew were injected into the patient's body.
No, the countdown started after the second shrink.