The trench coated angel watched with mild interest as he was appraised in much the same way that an ancient coin of inestimable value retrieved from a mythical sunken ship might have been appraised. It was an odd little device, to be sure, rugged metal with rather menacing pincers and a bright chartreuse light that singed strongly at one end. Soldier he may be, but a natural streak of inquisitiveness left him with a desire to know more about this not-man and his mysterious blue box. It had taken him under two seconds to sweep every inch of the city, but he could say with a dour confidence that no box matching its description could be found within these perimeters.
"I am not a man," he pointed out insouciantly, one not-man to another not-man, each an anthropologist of his own merit as they studied one another. "I am an angel of the Lord and the trajectory of our travel can be expressed in a series of partial differential equations." The letter on the bulletin board had pressed him for details about the not-man, and sure enough, the angel had provided the correct answers. But as it happened, the answers had been taken from his own observations rather than from the lips of the Doctor. He had heard about this specie that called itself Time Lords, as he recalled, but he had never personally met one. How fascinating.
Castiel looked on in detached bemusement as Amy Pond suddenly broke from what was clearly a heartwarming embrace until that point and began backing into him. This change in behaviour was illogical and incomprehensible. Was the Doctor not, after all, the not-man she had been seeking?