You must handle the dog you bring into the ring. You cannot call rat for a dog you are not handling nor remove the tube from a dog you are not handling. Note that if both dogs find the rat at the same time it doesn't matter who calls rat, but you can't call rat for the other person/dog. If you are handling the rougher dog then you may remove the tube, but it may be best for you both to restrain dogs after anyone calls rat.
There are no distance challenges in Team.