Quake II/Main Gate

Arsenal
Starting the Jail Area unit, you should have the following armament:
 * Blaster
 * Shotgun
 * Super Shotgun
 * Machine Gun
 * Chain Gun
 * Grenades

Unit objective
The primary objective for the Jail Area unit is to destroy the security grid protecting the Strogg industrial region.

Level objective
The objective for this level is to penetrate the outer jail defenses.

You arrive in the Jail Area in a small room under the conveyor belt from the Bunker Area. Make your way out the door onto a bridge over a pool of water. (See Secrets, below.)

When you emerge from the building you'll immediately face a few Flyers, Gunners and Enforcers. Negotiate a hallway with opposing ram barriers to get closer to the Main Gate building. The rams are deadly, but the safest way to get through is wait until the opposing rams meet, push against them, then move past as the rams part. By crouching you can see if any enemies are approaching from the other direction and kneecap them with your Blaster or Machine Gun.

From this point there are two ways to proceed to the objective. You can jump into the water and make a long swim through tunnels and conduits to attack from the rear, or take a direct approach through the entrance and save the swimming for later.

Stay dry
Proceed to the door and take out the Enforcers, Gunners and Berserkers you'll find immediately inside. (See Secrets, below.) From the door you'll first head west, down three steps, then right (north), left (west) down a few more steps, and left (south). In the room just before the security scanner — a pair of vertically oscillating yellow light bars — you'll find an explosive radioactive container that doesn't explode when you shoot at it. Push it to block the lowest laser barrier beam in the middle of the room before attempting to negotiate the security scanner, then quick-save the game. As you attempt to walk through the security scanner a grid of powerful lasers is triggered on the floor ahead and behind you where you placed the barrel. You can try to run-hop across it and find the shutoff button just to the right of the stairs on the other side of the room, or go back outside now, while the barrel blocking the laser beam barrier behind you is still holding. It is possible, though very difficult, to creep up to each red laser beam and hop over it singly, but you may find it easier to just take a run at it, aiming straight for the stairs across the room while quickly tapping the space bar a couple of times. Take advantage of the fact that the beams don't all come on instantly. If you time the hops just right, you'll land in the spaces between the beams and come out intact on the other side. Once you've deactivated the laser grid, continue forward until you see the main jail yard.

On the south side of the jail yard there is a guard tower and a howitzer. The shells from the howitzer are deadly, but taking out the gunner is possible. Before going into the open, scoot to the left side of the doorway, go forward a step or two and crouch down up against the door frame. It turns out that the howitzer can't be aimed that low and any shots fired at you will pass harmlessly over you. Aim your Blaster at the small space just below the gun barrel and keep shooting at the gunner's exposed legs until he splashes. Once the howitzer has been silenced, run across the yard and duck into the guard tower. Your run across the yard will lure out a Gladiator armed with a rail gun and a couple of waves of Flyers. Pick them off from within the relative safety of the tower. Once the coast is clear, step on the lift and ride to the top of the tower. Step onto the blue-pulsating tri-lobe foot switch to open the main gate to the Detention Center. The lift is one-way only, so to get down from the tower you'll need to jump and take some damage; stay close to the jail wall to keep damage to a minimum. (If you're very quick about it, you can dart out from the lift platform, press the switch, then back up quickly and ride the lift to the ground. It will continue to oscillate up and down as long as you stay on the platform, giving you a chance to grab items from the top floor of the tower with short excursions.)

In the rear corner of the ground floor of the guard tower find a cracked floor grate. Hit it with the Blaster until it shatters and climb down the ladder. Collect the items you find there and follow the passageway. When you come to the next room, you'll see a Gunner; take him down. You'll notice a pool of turbid, brown water. and further progress is barred. If you happened to catch the Gunner off-guard, he won't have had a chance to trigger the alarm system; press the yellow ALARM button in the southeast corner of the room to trigger an explosion that releases another Gunner just beyond the barrier. Collect a Chain Gun and Flak Jacket nearby. Also notice the red vertical light bar on the wall. It is the power conduit for ventilation fans above and a large propeller in the tunnel below the floor. Shoot it to break it. Jump into the water, swim past the stopped propeller blades and pop up in the pool beyond the barrier. Collect several items, including a Super Shotgun, Silencer and First Aid Kit. Jump back into the water and swim north into the watery tunnel. Follow the tunnels until you find your way back to the secret near the start of the level and ride the lift up to the starting point under the conveyor belt. Retrace your steps from the start to the main gate, picking up any items you can as you proceed. Go inside, step on the lift platform and press the button to proceed to the Detention Center.

Go swimming
This approach essentially reverses the map traverse described previously. Swim through the watery tunnels until you pop up in the large circular room with an overhead ventilation fan. Watch for the exploding wall that releases a Gunner. Shoot the Gunner on the other side of the barrier through the openings, then take aim at the red power conduit, shooting it until it breaks. Jump into the pool and swim past the now-stopped propeller blades and pop up in the pool beyond the barrier. Collect items, then proceed down the passage until you find the cracked grate above the ladder. Shoot it, climb up out of the hole and take down the Gunner minding the guard tower lift. Ascend the tower to take out the howitzer and activate the main gate foot switch, then return to ground level and take on the Gladiator and Flyers from the tower base. Go into the door on the north side of the yard to clear out enemies you may find in there. When you get to the room with the laser grid on the floor, if you triggered it earlier, you can deactivate it with the wall button by the stairs, in the northeast corner. Proceed through the main gate to the lift platform to get to the Detention Center.

Secrets
This level has two (2) secrets:
 * 1) Jump off the bridge into the first water area you encounter upon arrival.  There is a hidden opening under the bridge.  Enter the passageway to get a Rebreather and First Aid Kit.  A lift platform at the far end of the passageway returns you to the starting point.
 * 2) Inside the Main Gate building there is a yellow ALARM button on the wall.  If one of the Enforcers has  triggered the alarm by pressing the button, when you return to this room an explosion opens a secret alcove high in the wall to the right, releasing a couple of Flyers.  By hopping onto the ledge by the stairs, walking across a computer cabinet and jumping up onto a tall electronics rack you can, with difficulty, make a running jump into the alcove and collect a Flak Jacket.  If you were quick and killed both of the Enforcers in the entrance area of this room before they could trigger the alarm, you can push the button yourself to reveal the secret alcove immediately.