Mission 4: No Hope in Hadleys

4 Dog Tags
1 Audio Log
Gorman's Pistol

Continue following the path until you reach Hadley's Hope. Open the door and go straight ahead the derelict corridor. Enter the first room to the left to find the mission's only audio log on the table.
Worr

Follow the straightforward path until you reach the welded Operations door upstairs. Cut the door open and check the table in your immediate left to find a dog tag.
Operations Room Dog Tag

Loot the ammo and armor pickups nearby then operate the lever if Bishop haven't done yet. Once you get your orders to place motion sensors, follow Bella and Reid and wait for Oneal to open the locked door. Once inside, place the first motion sensor then enter the clinic beside it. You'll find the dog tag on the operating table.
Clinic Dog Tag

Continue placing the motion sensors on the marked outlets. After placing the last sensor in position, wait for a mission update. Reset the motion sensor that went offline in the morgue and learn that your location has been compromised. Make your way back to operations and fight your way through multiple xenos along the way. Once you've reached operations, repel more xenos pouring in. You'll then have to backtrack again to retrieve the sentry turret you saw earlier. Run back to the operations and deploy it near the ammo stash.

Repel another wave of xeno attack. After getting the mission update, pick up the smart gun from the crate nearby and continue to the next hallway. Drop down the opening on the floor and go downstairs. Proceed to the next hallway where there are multiple xenos waiting. Use the smart gun's auto-tracking and lock-on system to lay waste to the number of xenos waiting in the corridor. Push forward and and enter the room to the left to find a full set of armor and a dog tag on the crate near the wall.
Hallway Dog Tag

Proceed to the next room and fight your way through more xenos. After reaching an intersection, head left then drop to the lower path. Turn around to find the last dog tag on the ground.
Sewer Dog Tag

In the next room, there are three lurkers hiding in the shadows. These are really fast and dangerous enemies so make sure to melee them first to push them back a bit before blowing them up. This way, you'll avoid getting damaged too much. Use the smart gun's auto-tracker to locate and kill them. The mission will update afterward. Follow Oneal as he opens the door. Follow the path until you reach the next room. The mission's legendary weapon (Gorman's Pistol) is found on the table of this room.
Gorman's Pistol

Cut the next door open and proceed for a scene. The mission will be complete afterward.