After clearing the door, you will be momentarily free of Tyrant if you didn’t kill him. If you did, it will make the next few areas a little bit easier to handle. Now that you have escaped, you will have to activate two panels in order to unlock the next exit while wave upon wave of zombies spawns in the corner and attacks you. The panels will be marked via waypoints on your HUD. Sprint to the first one while firing to clear a path through the zombies all around you. Slip through the hoard, using the shoulder charge move if necessary to clear a path ahead of you, and make your way to the panel. Open up the door. You will find three parasite zombies inside of this small lab. Kill them quickly with headshots. Grab some Intel from the desk in the room and search the ground for two Green Herbs if you need to heal. When you are done with everything in the room, activate the console. You are now halfway towards escaping the facility.
Unfortunately, more enemies will spawn when you activate the panel on the console. Turn around and mow them down with automatic weaponry. As you leave, turn and head to the far side of the arena to find a room identical to the one that you just left. Just like last time, a group of three parasite zombies will greet you just inside of the door. Take them out and proceed into the small room. Pick up any ammo or First Aid Sprays as necessary and examine the second console to deactivate it. This will again cause more enemies to spawn and attack you from right outside of the room. Fighting the hoards outside is almost pointless at this point, as they will spawn frequently enough to make resistance gutile. Instead of fighting back, sprint through the crowd and run towards the exit. Along the way, you should find more ammo and a Frag Grenade by the wall. Toss a grenade if necessary to clear a path ahead, then leave through the exit at the end of the hall.
When you enter the next room, watch out for parasite zombies and collectibles. A small group of the possessed undead will attack you from the back of the chamber. Put them down, and then search the room and the adjoining room for two pieces of Intel, one in each. When you are ready to fight Nemesis (and possibly Tyrant, too, if you didn’t kill him before) head down the stairs.
