The Doom That Came to Roseway is a side quest.
Failure to return the Research Data leads to Anton committing suicide.
Even returning the data can sometimes lead to Anton committing suicide depending on how he is spoken to.
After getting the keycard, the map marker will show that you need to head back to Cassandra. She has no new dialogue options, so the map marker is actually pointing to the "lock" on Cassandra's cell, which is on the wall behind her. You need to go through several rooms to get behind the cell and find the lock to get her out or kill her.
|Quests in The Outer Worlds|