If they manage to invade Lara's personal space, blast them with the shotgun or use one of your Brawler skills to disable and finish them. For example, the Dodge Counter: When Ugly Dude here lunges at Lara, hold Aim (Right Mouse Button/L1 or L2/LT) to keep your weapon trained on him. Then press Dodge/Roll (Shift/Circle/B) while moving left or right.
If your dodge is successful, the Melee icon appears on screen, just like in the quick time events. Press Melee (F/Triangle/Y) in time with the prompt (i.e., wait for the gray circle to to contract into the inner ring and the Melee icon to appear, then press the button).
If you manage to do that, the Dodge Counter icon flashes briefly on screen, as shown above. There's no need to do anything now.
Lara takes over, in this case stabbing Ugly Dude in his filthy leg with an arrow.
Now that he's disabled, you'll see the Melee icon with a skull over his head. Either move in close and press Melee again to deliver a finishing blow or just blast him with whatever weapon you're holding.
After the cut scene and the awarding of XP, loot the bodies and pick up all the extra ammo you can carry. Then climb onto the metal crate at the front edge of the platform. Grab the zip line and climb across to the other tower. Search the fallen enemies here. The climb to the upper level using the yellow ladder or the wooden wall around back.
Off to the southwest is a climbable surface on the cliff side. Use the zip line already in place to climb toward it. When Lara gets about halfway across, the bad guys notice her and cut the line.
Keep climbing while Dumb shoots flaming arrows at you and Dumber hacks away at the rope. Before you can make it across, the line snaps free. Lara falls but manages to hang onto the rope.
Just like in the Mountain Village sequence, you need to press Interact when she reaches the cliff to latch on with the climbing axe. The men continue shooting at her, but before they can do any damage, they suddenly drop dead.