The priority is, surely, to vacate the runway to the extent that it is again usable? At any reasonable ATC unit air and ground controllers will work in harmony to the benefit of traffic. Eg the ground man will ensure that taxying aircraft will give way to an aircraft leaving a runway or, if it's not possible, the Air Controller will instruct the a/c to vacate and hold... or "follow xxx from the right", etc.. At many airfields the Air and Ground controllers are just one bloke and if he can't sort things out.........