(5) Aggressive solution: Get out of the Convention Center Deus Ex: HR Guide

During the attempt to leave the building you also need to take into consideration that the area might be still patrolled by some guards. As a result It's worth to return to the main corridor, take a look around and eliminate them if needed #1. An alternative way is destroying the nearby wall #2 which would let you reach the staircase leading to level 1. In order to perform such an action, you would of course need the Punch Through Walls augmentation.

Regardless of the chosen method, you have to reach the staircase #1. Head down and be ready to get rid of the last group of guards #2. They will appear here only if previously, for some reason, they haven't joined the battle and in such situation you will have to eliminate probably three people.

Go down to the last level and turn left. The area should be safe, so you won't need to stop. Quite soon, you should reach the Convention Center exit.