The Acropolis - Fighting Your Way to the Acropolis Tower (Part 1)

Lara arrives on the scene to find her Remnant allies under fire. The portcullis closes behind you preventing retreat. As far as I can tell, there's no way to sneak your way through this encounter, so you'll need to be aggressive. You may be able to take out one or two of the Trinity soldiers from inside the archway, but they soon spot Lara and start shooting. Kill the first man on the left if you didn't hit him from the doorway.

Then attend to the 2 soldiers ahead on the right.

You can probably kill them both with one poison arrow, especially if you've unlocked the Death Cloud Arrows skill, which makes your poison arrows even more toxic.

Same with the next 2 men who appear on the ledge above.

Cough! Choke!

If one of them manages to throw a grenade, quickly move out of the way and take cover behind another box, the big rock in the middle of the street, or one of the stone columns on the right.

There's one more guy on the far left, assuming he didn't succumb to your toxic cloud earlier. Kill him with your weapon of choice, and this phase of the fight is over.

Loot the bodies and gather all the ammo, grenade arrows, and other supplies you can carry. Don't miss the container of cloth and the strongbox (3/3) in the alcove on the east side of the street. This box contains the ENHANCEMENT TOOL, which opens up a new tier of possible upgrades for your weapons.

When you're ready to move on, use a rifle grenade or grenade arrow to destroy the metal barrier to the southwest and go through.