This is a rather dirty fix for point_viewcontrol entity, which was designed for singleplayer and doesn't exit properly when multiple players are looking through it.
- On deactivation, the camera will be deactivated for all players using it, one by one.
- Blocks kill and explode commands while being used by the player
- Using this, the OnEndFollow output will be called multiple times!
If you're a mapper, activate this entity via trigger for every player that should see through it. Deactivating it once will do so for all players.