The rats didn't seem like a particularly interesting object of observation; they were just running back and forth in search of food like ordinary rats, except that they had somehow grown to monstrous sizes.
"Hmm, I guess there's nothing else unusual here. Although, wait, I'll check something..."
Radiel finds a comfortable position somewhere on a balcony, out of reach of the rats, reverts to his skeletal form, takes out his flute, and tries to charm them like the Pied Piper in the story.
Added 4 minutes ago
No, worn-out underwear won't do.
Nikta requests a scent sample of the missing person. No, worn-out underwear won't do.
Added 1 minute ago
-- Psst, they have two mines here, but the blue one is abandoned (?), so he's probably talking about the yellow one? He should point it out. And the monastery is here," Henry drew imaginary letters "M" and "C" on the map with his finger.
Небо – угроз не слышит
Небо – ведёт особый счёт
Небо – тебя найдёт