You really think I didnt try that? only 2 ways of flanking up the lift and up the stairs to the side before you go outside. I just get killed by campers over and over again with 2-3 turrets everywhere. And this is versus the enemy a.i. seems to be about as smart as a human players and I get the special ed on my side squatting in a corner guarding an objective that doesnt need guarded and running right past me when im downed. I seem to run into alot less human players on the security missions.
Find a weapon that's just right for you- this is the most important thing of all. Complete the challenges, find a gun you are most comfortable with, then stick with it as you fight your way through gradually. Don't rush, because the enemy does full damage too. This is the problem most people have with the AI, in normal, singleplayer games they only do a portion of what you realistically do to stay at a managable level, in Brink they do full player versus player damage. Make full use of the slide+shoot style and keep in mind that you can cook grenades.