Copper Mill - Skirmish in Large Room with One Open Wall

After sliding down the rope line from the ledge with the locked strongbox, immediately take cover behind the metal box.

A group of Trinity soldiers see Lara arrive, so there's no sneaking up on them. You'll probably have worked out your own style for taking on small groups of enemies, but if you're struggling, here's what worked for me: Shoot the first man ahead on the right from behind the metal box using a poison arrow, regular arrow, or whatever.

Then scramble over to the box on the left and use the bottle to craft a molotov cocktail, while the next 2 enemies move toward you.

Throw the firebomb at them.

If either survives, finish him off with your weapon of choice.

Then advance and peer around the corner to the left. If you need ammo, you can loot the bodies as you go.

Hide behind the first metal box and take potshots at the 3 soldiers on the other side of the room and the sniper on the ledge above them.

They'll soon start throwing explosives. So when you see an incoming grenade or notice the red icon on the screen, run back the way you came to avoid the blast. Use a bandage (LB/V/L1) if necessary. Then advance again and keep firing.

There are more bottles and cans here if you want to make more molotovs or shrapnel grenades, but that takes time. If you shoot an enemy just as he's about to throw his own explosive...

...you can make him fumble and set himself on fire. Or simply alternate shooting then releasing LT to duck until you're able to take out the rest of the men.

You may need to move forward and take cover behind the smaller box on the right in order to get a clear shot at the sniper. There's pistol ammo here if you need it.

Once you kill him, the fight should be over.