Pokey, Visionism's stealth or sneak approach is fun ... I went the catwalk route. Ran and jumped over the railing onto the crates, hopped to the floor, took the guard down ... little or no damage. Used the DNA and grabbed the gun. Got my back to the wall, next to the crates, and got ready. Two guards came thru the door ... down they went. I took very little damage, had all five blocks full. Went thru the door took care of a few more by using forward and back, closing and opening the door. I think there was an explosive barrel in there that really finished them off. The rest of the way it was stealth and scalpel.
This lead me to the room with the four guards and the Riot Guard, which is the robot your referring to.
After you kill the last guard in this room the Riot Guard comes down in the elevator. You need to climb a box, then one more up. He will usually start for the crate once he sees you. Drop back down on the lower crate, give him a second or two, climb back up to the next crate, and he will usually be standing pressed against the crate under you. Just shoot straight down at him. One or two shots should do it. He can shoot, but he can't aim high enough to hit you. Check out the crates near the door you entered the room from.
You'll run into these guards quite a lot. The only way you can kill them is by shooting them in the back. Until later on, the best approach is to avoid them by using stealth, or lure them into a situation that something else will kill them, like something big falling on them, or run like _ell. I used stealth.
Use your Quick Save to experiment with different approaches ... that's fun too.