The second time you push it, it detonates, doing damage to enemies around you. The first time you hit the button to activate the power, damage taken will be decreased but your power cooldowns will also lengthen. (Fortification and Defense Matrix come to mind as being very similar) It's a little confusing though since I think in previous iterations there weren't any powers that worked this way. Tech Armor is a two-stage power, of which there are several in this game.
