You may point out that Loki's was a special cell created for a super-being. But it's really the default design in the corrections systems of action movie universes. In Skyfall, terrorist and former secret agent Silva's big plan is to get caught, escape, and then kill M. The heroes -- who are very experienced with this type of guy and this kind of plan -- know that only one kind of cell could ever hold such a monster! It could also double as an aquarium:
Star Trek Into Darkness puts Khan behind a glass wall, mostly because movies decided long ago that Glass = The Future ...