the golden wrench campaign from kobble has changearea and loadingfreeze events that do this, use the gamemode.cs file
you might want to play the campaign first and learn how it works in custom
it uses zones instead of clickable activation which can feel erratic, i would recommend using them one build at a time instead of hallway transitions
also loadingfreeze doesn't literally stop the game, it just holds the last frame of your screen for 5 seconds, meaning anything can happen to your character during those 5 seconds