This is the front face of the enemy base. There are 2 ways in. Through the underwater entrance, or through the front door. I sugesst getting 2 demos together to blow through the underwater tunnel and sneaking in through there. Demos are dumb though. Have to beat it into their heads to open the passage.

Underwater, there are 2 concealed passages at the bottom of the lake. REMEMBER LEFT IS ENEMY! I hate it when people pop up in their own team's base not realizing it. Remember to move quickly. Air is sparse, and you need all the air you can stomach to get through this without choking

This is the quickie way into the base. Through the tunnel. It requires 2 dets to open, and can be sealed off by the enemies. There is a few bottomless drops, one at the end of a dark tunnel, and the other in the middle of the passage. BE CAREFUL! Sometimes a jump won't land correctly, but we all have to suffer that sometimes.

This is the front door. They arent marked, But on the ledge to your right in this shot, look out for sentries.

This is the main courtyard. Sometimes an intrepid engineer will put a sentry in the corners under the guard towers, but not usually. keep an eye out though. Most sentries are on the upper ledge. You can get there from here. Just follow this handy guide:

Run to the room marked G above, and toss gas into the respawn in front of you. If you move fast enough, noone notices. It's cheap but effective. Go right, to the bathroom.In the bathroom, don't pick up the soap, just jumpup the lockers and onto the terrace. Take a left to the get to the upper ledge. NOW the fun begins!!

The last pic is of the upper ledge. This is where all the spy action takes place. EXACTLY opposite the door you just came out of, there is a ramp down to a resupply area. You can get into this one, but DONT touch the red tape. Use this room to your advantage. The L points to the entrance to the sniper loft. That is fun.
Sentries are sometimes built on the top of guard towers. Grenades can't get these, but nails can! hide just below the roof of the tower, so you can see the gun, now pound away! The gun can't see you, but you can kill it easily!! Just don't let the Engineers get you. There are usually a bunch on the upper level. If the gas is pulled, there are 5 masks easily accessable. 1 at each corner, and 1 at the sniper loft. use them! It makes infiltration easier.

This is the sniper loft. Knife snipers, and drop down to the ledge above the entrance to toast sentries.

If you have a yen to do a gas run, Run into the hallway marked F. take a left or a right, they all lead to the same place. (left leads directly there) Follow the F's to the flag. There. Now you're halfway done. Now run like the wind to the other side of the enemy base. The hallway marked G.

The best bet is to again go left from the G-hallway. This will bring you to the picture above. follow the G's and pull the switch. There. You gassed the bastards.

This is EXTREMLY HARD TO DO ALONE. If you want to try, toss grenades and gasses in front of you as you run to fuck up the opposition. There will probably be sentries in these areas too, so be sure to clear them out not just for your flag run, but for the rest of your team's runs as well.