Plot hole: Even if the white blood cells will attack and destroy the sub and the body of Doctor Michaels the atoms would still remain and take normal size after the critical 1 hour is up. This would also apply to the laser gun which they forgot or left behind on purpose, as well as several dozen litres of saline solution which were miniaturised and pumped into Benes' body. He's in a lot of trouble.
Fantastic Voyage (1966)
3 plot holes
Directed by: Richard Fleischer
Starring: Donald Pleasence, Raquel Welch, Edmond O'Brien, Stephen Boyd
Revealing mistake: It's painfully apparent that the actors are hung on wires pretending to swim while outside the sub.
Dr. Duval: The medieval philosophers were right. Man is the center of the universe. We stand in the middle of infinity between outer and inner space, and there's no limit to either.
Question: Just an observation. There's 5 or 6 minutes of screen time between the initial shrinking of the sub / crew and the start of the 60-minute clock. Shouldn't those minutes have been included in the countdown?
Answer: The sub was shrunk in stages, with the lab personnel performing different tasks at each step. The clock automatically reset after each step was completed and as the next shrink phase commenced. The final sixty-minute countdown began after the last shrinking stage and when the sub is injected into the scientist's body.
Answer: I think the countdown began after the crew were injected into the patient's body.
No, the countdown started after the second shrink.