Yes you can? I do it all the time! Kill as many people as you can a with an AR, then when you are about to die activate it and you eat shots and regen as you slaughter people. Activating in the middle of a gun fight allows you to kill some one while they are reloading because you just turned into a bullet sponge. Don't say it's not a panic button and that it takes skill. It clears out everyone capturing a control point easily.