Reach Solutional Haunt
- Look for an Access Node in the third environment group; Treeborn Colony is an exception. Activate it, complete the teleporter event including the extra Solus Amalgamator, and enter the Encrypted Portal to Conduit Canyon. Repurposed Crater also offers an Access Node route in the fourth environment group.
- In Conduit Canyon, kill Collective elites for Sentry Keys. Supply Sentry Terminals to remove force fields. The inner structure has three terminals, and the three near the teleporter need keys before it can activate. Save keys for the required route before spending them on optional chests.
- Start the teleporter. At 75% health, the Solus Control Unit is replaced by Alloy Hunter. Finish the event and continue to Solutional Haunt.
- Reach the lower area, activate both Heat Vents, and defeat Solus Wing behind the opened door.
Collect two Prison Matrices
After Solus Wing dies, the left cave opens. Find two Solus Coffers: one beneath the central tower and another on the distant high platform. Take one Prison Matrix from each.
If Umbra MUL-T blocks the return from the far platform, clear the enemy before heading back.
Open the vault and free Drifter
Return to the prison area on the right of the entrance. Spend the first Matrix to open the vault door, then use the second on the cage inside to release Drifter. Both are consumed.
Confirm Lost in Transit and check Drifter in the next survivor selection. Defeating Solus Wing alone is not the unlock. You do not need Encrypted Cerebellum to rescue Drifter; save both Matrices for the rescue before considering their crafting use.