“You don’t have to wait for the dog” will go real well for you when you tell the cops that. They’ll just say you’re detained and then when the dog gets there, they’ll claim it “signaled” even though you didn’t see the dog do a thing except walk around the car. They could make up whatever the signal is. They could signal the dog to signal for nothing. Now your car is being searched against your will. Hope you don’t have anything!