[Ah, see, now she's speaking his language. Sentimentality does not appeal to him on the surface level, and certainly not so soon after being pulled into a strange new world, in an eerie, empty city.

But as a device to aid in investigating and recording clues? That's another matter entirely. Weir's mind is already churning in that direction, and it's reassuring to hear that she's giving it some thought, too.

Maybe she has a brain in that head, after all.]

As you said, a "frame of reference." If it can truly capture a single moment in time to the degree you seem to imply, then it's an indispensable tool.

[Oh, he could have taken a picture of the city map he saw in the station...]