Night in the slums wasn't quite what they expected. The pale light of the streetlights bathed the asphalt, there wasn't a soul walking the streets and the only movements they spotted was caused by mice rummaging through the thrash.
Uriel was fairly certain that Luna was wrong and that people's disappearance was caused by rogue hunters who turned to crime, but he couldn't deny the value of empirical investigation. Even if there wasn't a way to disproof her theory, they could prove it just by walking the streets with an open eye making it a proper investigation. Though Uriel set the condition that, in the case they didn't find anything, Luna would give up on breaking the curfew in the future.
This made their endeavor a win win situation for Uriel. If they found something he could take the flux orb, but if they didn't he would get Luna off from his back.