Enemy-controlled doorway inside the castle's saferoom hallway, expected to open onto automatons or a bomb.
Somewhere in the situational hallway near the saferoom exit sits a door belonging to The Reavers — the product, Carl reasons, of someone on the Reaver team getting through the old bait shop door back when this space still belonged to the mantis team. It is the same trick Carl himself used to create utter chaos in Zockau with an inconvenient doorway.
Rosetta warns that at any moment the Reaver door will open and flood the castle with automatons, and she sets up defenses and flamers to meet them. Carl reads it differently and worse: the enemy is deliberately stripping the interior protections through the worm-puppeted Lonnie, and once enough of those protections drop simultaneously, what comes through the door will be a bomb. That is how he would do it. Elle waits in the hallway for whatever emerges.
An unremarkable interior doorway in the castle's situational hallway, inherited from the space's previous mantis-team occupants.
The enemy's foothold inside the castle and the anticipated delivery point for automatons or an edifice-destroying bomb.