Sherlock snapped out of it, the strange infrared glow overlaying his vision. He could see that Will obviously gave off heat, and the rest of his ordinary eyesight let him deduce what he could from his appearance.

"I probably will be...do you know anything about infrared sensing in lizards or snakes?"

Random question, probably. He was clearly a new person, and at one point Sherlock would have felt sorry for them. But now...now it was different. He could understand why people voluntarily came. Or stayed.