Doom's got nothin' on Dum Dum
For our second tactic I switched from Deadpool to Magneto, to block the entrances with a larger body so Dum Dum couldn't rush in by himself, preserving as much of his health as possible. This got us to about the third room, but still ended in failure. Playing by the games rules, we even tried telling him to hang back using the in-game commands, but they had no effect on the stubborn old man. Needless to say, we failed quite often with the message "Dum Dum Dugan has died" flashing on our screens prompting mild profanity to fly over our headsets.
Just when we were considering starting the whole game over with the difficulty on normal, Arttemis tried something insane. When we defeated at the first "Super Soldier" miniboss, Nightcrawler (Arttemis) teleported through a wall that led us to the end of the first escort area. Having Deadpool in the party, I quickly followed suit with a teleportation of my own, leaving Dum Dum to a cleared room with no enemies to drain his pathetic life bar. We proceeded to clear out the rest of the enemies without the cowboy-hat-toting tag along, before triggering a cut-scene which brought Dum Dum back up to our position.
The rest of the level had a few small quirks, since we managed to glitch the game to avoid overall Dum issues. Such as the version of Dum Dum Dugan with no health bar randomly joining us in battle to be quickly shut down with a game-ending failure. Eventually we figured out how to get beyond his reach again and again to keep the silly old man alive, triumphing over the Dum Dum Dugan escort through cooperation, creativity and the power of teleportation!