Wait for their conversation to end, at which point the two men go their separate ways. If you take care of them in the camera's view, things won't go well. You'll come up on two more guards who are talking while standing in front of a security camera. Continue down the hallway and proceed cautiously. Wait for him to finish, then attack him from behind with a melee attack to eliminate one threat. You'll find a guard talking into a radio. Follow that hallway and you'll find a terminal that you can hack using your phone. Cross the lobby and pass through the door on the far side. Climb them, then head between some guards and into a lobby area. Then head up some stairs located along the left side of the area. You'll add some intel to your collection. In that common area, start by scanning the statue at the center of the courtyard.
The guard who was stationed at the gate that you needed to open will rush out to fix the annoying alarm, leaving you free to head through the gate and into a common area. Find Pomerov's car, also marked on your phone's radar, and play a hacking mini-game to set off its alarm. A guard is stationed at the gate, so there's no obvious way to get to it, but there is a possible solution.
Now head for the gate that we mentioned just a moment ago. (Above Right) When the guard leaves his post, head through the gate and make your way to the lobby. (Above Left) Hack the car's alarm to create a distraction for the guard at the nearby gate. Hack it with your smartphone by playing the mini-game, then step inside and head left to find a computer that you can scan to gather intel. There's a security scanner to the door's left. Before you worry about the gate, though, cross over the yard to the building that you see as you first leave your starting point. Leave the shack and you will find that there's a gate not far to the right.