Well their perk is called Unstoppable and they're the tankiest class. If they're not Super tankier than everyone else at base it makes sense to have their tankiness emphasized during their Super's duration, especially considering just how short a time it lasts. You could try Twilight Garrison, but you'll really only be able to dodge Death From Above FoH's when they're activated further away. Up-close you're vulnerable, which is pretty obvious. They're the melee-range powerhouse. They deserve as much, at least. And for you calling it a panic button, Blink and Nova Bomb are also pretty much panic buttons. One's not lethal, but it's certainly saved someone's sorry ass from a bad call on more than one occasion.