Although I’m quick to point out logic flaws in SF movies, I take issue with two of the cases cited.

1. Seth Brundle (played by Jeff Goldblum) getting in the telepod.
Defense: Brundle misinterpreted something his girlfriend (first ever) said, got upset, got drunk on flat champagne and stepped into the machine. People have done stupider things, even without alcohol.

2. John Hurt’s character not being quarantined in _Alien_.
Defense: Ash, the android sent by the company, knew perfectly well there was something implanted, but he wanted to see what would happen without medical intervention. So, he told Dallas and Ripley the guy was OK, let him go and kept an eye on him until… “There may be some blood.” It’s called amoral science; remember, the crew was expendable.