Installation Vista - Supply Depot with Lenin Statue

Before advancing, pick the herbs growing on the right near the metal platform. If you like you can scramble up onto the platform to get a bottle, but don't stay up there too long or you may be spotted. Move around the left side of the platform into the bushes.

Now use Survival Instinct to scope out the situation. A tutorial reminds you that enemies highlighted in red can see each other so killing any of them will alert the others. Enemies that glow yellow can be killed without attracting attention, as long as you do it quickly and quietly. If necessary, you can throw bottles or lanterns to draw one enemy away from the others, but that probably won't be necessary here.

Take out the nearest man, either with a headshot from your bow once he's standing apart from the others, or by waiting until he approaches and using a stealth takedown.

Now, if you're patient, the 2 guys in the middle should split up. Kill the one on the left with a headshot.

Then go for the 2 inside the building. The one on the lower level mostly keeps his back turned...

...so you should be able to line up a headshot.

The one above tends to pace back and forth. If you can't manage a headshot, use two quick shots in succession, which you can do more easily if you found the Ancient Abilities codex in the Ice Ship Challenge Tomb.

Finally, move around to the right...

...and finish off the last guy who seems to be romancing a wooden storage box. Either sneak up behind him for a stealth kill or take him out with a quick headshot.