Section 20: What Kept Me Going

Sarah is frustrated as her work is stalled due to a lack of a DNA synthesizer. You suggest looking for one at her old lab in Cloverdale, which requires traveling over Thielsen Pass into Iron Butte territory.

Stock up on ammo. With Sarah riding double, head for Thielsen Pass. A sentry will stop you, but Sarah convinces him to let you pass, though he will report it to the Colonel.

After descending the mountain, you'll encounter the gruesome work of the Rippers. Team up with Sarah to push a vehicle blocking the way into a cluttered tunnel.

Navigate through the wrecked vehicles in the tunnel and continue to Sarah's old lab at Cloverdale.

The facility's fence is electrified. Sarah uses a palm reader to open the entry gate. Inside, you find flourishing corn fields, but are attacked by infected crows. Take refuge in a car until the birds depart.

The mission transitions to "I Knew These People." You find corpses of Sarah's former colleagues, shot while trying to leave.

Sarah cannot access the lab via the usual terminals. After failing at a palm panel, you notice a security camera, suggesting someone is intentionally locking her out.

Follow Sarah to an elevated fire escape. Shoot the latch to lower the ladder. Climb up and use the emergency panel to open the door. Sarah believes Jim, the security guard who hassled you earlier, may still be inside.

The mission transitions to "Expect The Worse." Upon entering a warehouse, an alarm is triggered. Eliminate the three security guards below, then shoot the alarm horn.

More guards will appear from the far side; eliminate them. Climb the stairs and deal with guards on the walkway above.

Sarah overrides the facility lockdown to open doors. Gun down guards in the connecting corridor.

A sniper on the roof to the right will engage you; shoot him through the glass. Eliminate two more guards on the left. Shoot the speaker to silence the alarm.

Sarah opens the next door. A technician runs into the atrium, and the doors lock behind him. Search the office for supplies. Sarah remains locked out of the atrium.

Sarah suggests heading to the roof to create a diversion while you open the atrium doors. Boost her onto the roof. As gunfire erupts and she taunts defenders, use the access code to open the doors.

Engage the eight security guards in the atrium. Deal with guards on the balcony first, then those below. Some may come up the stairs on the far left.

Once the atrium is secured, head up the stairs and bash open the lab door. Jim, the security guard, is inside. Sarah needs him alive.

Sarah confronts Jim about the security guards killing the workers. She forces him to open her lab at gunpoint and then kills him for his cowardice and treachery.

Sarah reveals that an intern, David Gorman, suspected a government plan to weaponize her research. She explains how he hacked a computer, stole data, and accidentally released the infection at a conference in Portland, leading to the global plague. She realizes she was used and played a part in the devastation.

The mission transitions to "We Couldn't Take The Risk." Sarah has the DNA synthesizer, and it's time to leave.