Went back and tried it this way. Legacy power to Lifeline, draw to Legacy, then Lifeline’s turn, power, draw to Legacy. Blade didn’t get to heal this way, but he got his force field which was even more annoying on the flip side until Lifeline blew it up. Ended up with slightly less HP totals and still 16 in the trash. Lifeline got to deal more damage this way with his Ax and Immolation. Oh, and Countermeasures did accidentally trigger for me once, but Blade was so close to beaten by then it didn’t matter a lot.
P.S. Back-to-back Take Downs skipped two Hasten Dooms. I destroyed both Device Assembly Lines ASAP. Suffer the walking tank to remain in play. Don’t make my same mistake and think it plays an environment card when destroyed. It’s a villain card, which could get really nasty.