Once you have collected all of the Intel in the area, examine the security console at the back of the room to unlock the security doors in the rest of the facility. Several doors in the room will now burst open and zombies will begin to flood out of them. Chuck a grenade into the room where they all begin to swarm to take out a large chunk of their forces before they have a chance to attack you. Mow down the rest with a combination of gunfire and melee attacks, drawing them into the room before you strike them all down at once.
Head into the side room and grab the Intel from the table in the corner. Pick up the Green Herb on the counter if you need the health, then head back into the room where you activated the security consoles to upload all of the Intel to the Laptop. Leave the room and head back to the lounge area. Walk up the stairs here. Watch out for the next wave of zombies, who will occupy the top of the stairs. Toss a grenade up the steps or wade into the fray with a Shotgun to make short work of the braindead enemies. After they are all dead, look at the ceiling above the stairs. You will find another Security Camera on the slanted ceiling. Shoot it to get more experience points. If you don’t see it now, it’s possible that you already took it out with the grenade.
Grab all of the ammo you need from the refill boxes at the top of the stairs and head out through the doors at the back of the hall. You will come into the next room directly behind a group of Spec Ops soldiers. Don’t give them any time to realize what’s going on. Hit them with a Stun Grenade if you have one, and take them out while they’re still convulsing. A wave of zombies will emerge from the far side of the room, and another room to your left. Take them out as they shamble towards you. Also, although it won’t be incredibly useful in this relatively easy encounter, keep in mind that you can wound Spec Ops soldiers by shooting them in the legs or arms. Once wounded, the enemies will bleed and attract zombies. In encounters such as this, when you are facing a mixture of human and zombie enemies, it can sometimes be best to wound the humans and let the zombies do all of the work for you. Once all of the zombies have been killed, look behind the overturned file cabinet in the middle of the corridor to find a piece of Intel.