We go back into the tunnels
We rebuilt the school. M'Toya held a meeting with her apprentices. M'aiq was told he need to teach/supervise Tress. Sa-cha on their daily run to the well healed Doris with the help of Rasmus. Doris said "It sees you".
The group convinced Adrick to let us back through the door into the tunnels with a promise to seal the door from the inside. We learned Mantike went down there with an Aasimar friend before we did. He had previously received a visit from wizards that asked him firmly to close the door and never let anyone else in.
Once in the tunnels, we encountered and defeated dirge worms. While fighting, part of the tunnel collapsed, blocking our exit and effectively sealing that door shut.