While it is possible to blast your way through the next section, we're going to take the peaceful route. The armed cop will be helpful later, so depossess his body. You must stay out of his view, so depossess him under the stairs, then quickly run up.

When you reach the top, your head will start ringing, and your halo will turn red. This means you have a new mission objective. Press your objectives key (F5 is the default) and read the message.

At the end of the catwalk is a worker near another stack of boxes. Possess the worker. Use the detonator on the boxes, then step back. The boxes will explode, revealing a door and a box of ammo. Open the doors and step through.

Make sure you are not in combat mode (hit the action key to get out of combat mode if you are unsure). Run past the guard and down the stairs to your left. At the bottom, you'll find two scientists. One is obscured near the gate in the back: He's the one you want. Depossess the worker.

Once you're out of the body, run to the scientist near the gate and possess him. The other scientist may request your help with his duties. Ignore him. Run back up the stairs.

Continue up the second staircase and step in the circle in front of the shielded door (if you're not in a scientist's body, you can open the door by shooting the circuitry to the right of the door. Follow the blinking yellow light to find it). When the door is open, run in and activate the access controls. This will open gate 04.

Gate 04 is on the bottom floor of this compound, to the right of the stairs. Open it and enter the sterilization chamber. When the sterilization process ends, open the second door. There are two exits in the next area: a staircase blocked by beams and a locked gate. Next to the stairs is a stack of boxes. Jump to the top of the stack, where you'll find a machine gun. Leave it - you'll need it later.

From the top of the stack, jump over the security beams onto the stairs. Walk up and quickly depossess the scientist, then quickly run past the cop behind the gate.

Jump off the ledge and glide to the left. There's a series of outcroppings you can climb. At the top, you'll find a short passage that leads to the fan room. Drop to the bottom of the fan room, where you'll find three buttons. These control the fans. Activate the middle button once, which will raise fan #2 to its middle position. Activate the third button twice to raise fan #3 to the highest position. Leave fan #1 alone. Now, climb up the outcroppings near the first button until you're level with fan #1.

The fans will give you a considerable boost when you jump onto them. Use this technique to jump from fan to fan until you reach the reactor control room. Possess a radiation worker. If the power has been shut off, activate all four console switches to reinstate power. Get in the elevator, which is located near the first power switch, and ride it down.

Exit the reactor core through the door directly across from the elevator. This will take you into the command station. Do not attempt to get past the guard in your current host. Instead, walk around to the repairman near the gate. Depossess the radiation worker and possess the worker. Now, walk over to the guards, who will let you pass. Once the guards have turned their backs to you, depossess the repairman and possess the commander. Make sure to do this behind her back, so she doesn't alert the guards. Stand in the red rectangle to receive the emergency transmission, then activate the access control to unlock gate 05. Run past the guards and go through gate 05.

It is very important than you remember to not be in combat mode when you are around other armed officers. Even though you are in the body of a commander, they'll shoot you on sight if you're hostile.

Once you go through gate 03, you'll be back where you started. Step on the circle to open gate 02, then take cover. Kill the chots as they emerge. The light cop should help with the fighting. If the commander dies at this point, possess a chot. Once you've taken out all the mobile unfriendlies, go through the gate.

A chot with a rocket-propelled harpoon blocks the final gate. If you're in the body of a chot and all the fighting is over, you can just stroll up and possess him. If not, you must fight. To do this, keep crates between you and him, then move to the far side of the room. There, you'll find a bazooka. Pick it up, then stand behind the box. Jump and fire at the chot; just make sure he doesn't hit you. Once he's down, a few more will enter. Once every chot is dead, you can open gate 01 and enter old town.