Ritual stuck with no monsters

Bug Report ID: #2215129

Hello,

This occurred during a ritual in a Crypt map.

Turns out this isn't a bug per-se, but there was one monster hiding in the ground, and I thought I had run all around the area to release it, but it took a good minute or so to find it by accident.

It would be nice if there was an easier way to find/indicate the lost monster.

Thank you,
Kewlkarl