The massive circular fortress looks extremely technological from the outside. The fully enclosed dome makes it appear more like a secret research base rather than a prison. The thickened metal walls and multi-layered defensive barriers make this place impregnable. Let alone sneaking in unnoticed from the outside, even using props to blast through might not open it quickly.
However, Red Stone had already instructed them that there would be someone at the entrance to assist. First, a few people needed to go in and create chaos, and then the others would enter through the emergency exit.
Judging by the defensive barriers, this Punishment City hasn't completely isolated props, and it's relatively far from densely populated areas. Even if something were to happen, it wouldn't easily affect ordinary people. Such arrangements significantly indicate that there won't be any interference devices.
