There are 2 boxes of rifle/SMG ammo and a crate of grenades sitting on the ground to the left of the doorway. Grab them. Then follow the on-screen prompt to destroy the metal barrier: Stand well back from the door to avoid taking damage when the grenade explodes. Equip the rifle, hold the Aim button and instead of the regular fire button, press Alternate Fire to launch a grenade.

Move through into a dimly lit room with another wide doorway on the other side. Pick up more rifle ammo and grenades just ahead on the right and then take cover as another squad of Solarii approach from the courtyard.

Don't waste grenades, but don't be afraid to use them either, especially if there are a few enemies grouped together—like the 2 riflemen near the water barrels on the right side of the courtyard.

Boom...and splash!

Shooting out the spotlight on the far ledge makes it easier to see the bad guys as they sneak up.

Like this weaselly bastard.

Once you've taken care of the first couple of guys, you'll need to move out into the open a bit. This is a good time to run out and grab the rifle/SMG ammo near the pile of corrugated metal, plus more rifle ammo and grenades ahead on the left. Moving out triggers the appearance of 4 more enemies: 2 with rifles and Molotovs, one with a shotgun and one demo man.

Shoot the one with shotgun as he approaches.

When the enemies start throwing explosives, move to different cover. Here Lara evades the demo man's dynamite by moving up to the low wall on the right, where she can also pick up more grenades.

If you manage to shoot him while he's preparing another charge...

...he'll fumble and blow himself up.

If things get too intense, don't be afraid to run back to the doorway.

After you've killed several of the men in this group, 2 tough guys with gas masks and rifles appear in the building on the far side of the courtyard, near the spotlight.

If you don't kill them quickly—with a grenade, for example—they'll drop down and hide behind the low wall near the bottom of the steps. Take cover when they shoot at you and then pop out and fire at them while they're reloading.

Finish off any stragglers. Then loot the bodies and pick up more grenades, on the right side of the landing between the 2 flights of steps, and on the left side of the right corner of the grassy area with the cherry trees. The Solarii Fortress Day Camp is in the far right corner.