Ok, so I’ve been stuck on the “true ending boss” for 3 days…

I’m not joking when I say I’ve probably done the fight, over 60 times. I can melt everything in seconds, but everytime I make it to phase 3 I’m all out of repair packs, and have no health left. And that’s where I keep dying… Literally I can get to phase 3 in probably less than a few minutes, but I just keep dying on phase 3. Why….