Flailing flask's of fire, forward at the foe (ok I'm done now), the party manages to not get any direct hits. Misses by 5 or less are still doing half damage, and misses by more than 5 do 1 dmg. So you are chipping away at the swarm. The cockroach swarm angrily hisses, moving towards the door to chase the party. But as soon as a cockroach reaches the sunlight from the door, it retreats.
The swarm is currently stopped at the doorway, both trying to chase the new smells of the party, and resisting going outside into sunlight. Back to Variel, then Kiryu, Eko, Maura. Maura is no longer nauseated.