Any Time Lord
Gray headed out of the hotel, searching for a TARDIS, or a Time Lord. He didn't really care that the Doctor had asked him to drop it, he wanted to find a way to help him. Because he couldn't believe that anyone, much less the Doctor, would deserve that.
Spotting someone who looked vaguely familiar from the last time he was here, and doing a lot of watching people, Gray sped up, calling out, "Hey! Wait up!"