Sorry to burst anybody’s bubble, but IR does not allow one to “see thru walls.”
I work with IR cameras all the time. All they do is perceive the IR reflected from or emitted by a surface. You can make educated guesses about what is below the surface based on this information. But you simply cannot “see thru” a wall and observe the people moving around inside.
Although there are some interesting capabilities. You can see through fog almost perfectly. Plastic, even “opaque” black plastic, is quite transparent to IR, while most types of glass are mirrors.
You can look at a person’s image and generally tell exactly what type of undergarments they are wearing. Or not.
I’ve never tried it, but I would assume the heat sink created by a hidden gun would show up well under someone’s coat.
Didn’t burst my bubble, still, it would be kewl to be able to spot an overheating bearing or circuit, and night vision (with or without an IR illuminator) doubly so.