Declassify Mission: Health doesn't regenerate
If you activated the mission, go slowly and keep your distance from the enemies. You should also prioritize carrying Stim-gas grenades instead of frag grenades so you can heal yourselves as necessary. Carefully continue downstairs until you reach outside. Here, more enemies await. Keep close inside the staircase so you can fall back to safety and ambush enemies. Don't hesitate to use the stim-grenades as often as needed.
After clearing the enemies, head to the exit but don't end the section. To the left of the exit, you should see a COG tag skull on the wall. Now head past the section's end door and check the base of the light post to find this COG tag.