So a vault room would be some type of room that you could get really good upgrades or have a 4x speed upgrade or something like that. My vault room has a 4x speed upgrade and unlimited ammo for all gadgets.
First you need to make a separate room for the vault. Mine looks like this (ignore the upgrades for now):
Next you need to get a vending machine. Put the vending machine in you original battle royale map. Make the featured settings like this:
Make the transmit on channel settings like this:
Make grant item settings like this: