Dylan finds a body with an exploded head, and the circumstances do not add up. Crossing the Threshold is an investigation across Central: review the security footage, dig through the Field Hospital archives, trace the victim to the Dig Site Threshold, and finally confront whoever — or whatever — is responsible. It is one of the three side quests feeding the Threshold Researcher trophy, alongside Unsupervised Science and The Last Taxi.

How to Start

Go west of the Field Office area to a garage door that slides open, revealing the body with the exploded head inside. Interacting with the scene adds the quest to the log. The only requirement is reaching the Central region, so this can be one of the earlier side quests a player picks up.

Walkthrough

1. Investigate the Loading Docks

The first stop is the loading docks themselves — inspect the security camera mounted in the corner of the docks.

Find the CCTV Footage. Head to the Security Station near the fast travel door and use the computer in the corner. Choose "Next Screen" and then "Interact" to pull up the footage, which moves the investigation forward.

2. Investigate the Field Hospital

Next is the Field Hospital, also in the Field Office area. Go inside, inspect the items scattered around the room, and then take a close look at the green cabinet in the corner.

Get the Archive Cabinet Code. The cabinet is locked, so go to the building to the south and climb to the third-floor SECURITY STATION room. Use the computer there, choosing "Next screen" twice, to learn the code.

Unlock the Archive Cabinet. Return to the green cabinet in the Field Hospital, open it with the code, and take the "Dig Site Threshold Quarantine List" note from inside.

3. Investigate the Dig Site Threshold

The trail now leads to the Dig Site Threshold. Report the body on the ground, pick up the nearby collectibles, and report further to Zoe. Interacting with the body grants the Mobile Research Station Keycard. Then jump up to the building to the north with the TE Clearance door — it is now openable. Inside, grab the recording collectible by the door and the note sitting further back in the room.

4. Find Wilson at the Warehouse

Head northeast to the warehouse. Hiss attack as soon as Dylan enters — clear them all out, then interact with the door on the north side of the room.

5. Talk to Wilson

Interact with Wilson inside the room. This conversation matters: Dylan's responses determine how the rest of the quest plays out. Listening Wilson out opens up an option to take in the entity and carry it back to the threshold rather than taking the straightforward route.

6. Host AVP-3

If Dylan agrees to host AVP-3, interact with the person sitting on the ground nearby to take the entity in.

7. Take AVP-3 to the Dig Site Threshold

Return south to the Dig Site Threshold and stand in the yellow square area to release the entity. Doing so completes the mission.

Rewards

Crossing the Threshold rewards the Untapped Practice Knot artifact and the Sensory Restraint Hood. It also counts as one of the three side quests required for the Threshold Researcher trophy. Nothing here is missable — unfinished objectives remain available in post-story free-roam.