Lol, I came into the gym, faced all the other trainers, and I went and healed. I come back, remembering the trouble I originally had with her (In Gen 2) and all of the stories I've heard.
I don't remember exactly how it happened. But, I beat her clefairy, easy. Then milktank. I think it attracted one or two of my pokemon, and I got a hit or two on it... Then Rollout, I think two hit my Flaaffy, KOing it, then I sent out Pidgeotto, to get a quick attack, it got Rolloutted. Then (It was probably at like half health then) I sent out Croconaw, and it took it out in a turn or two. It had no chance to use Milk Drink because of rollout 5 turns/a miss.
I guess I got lucky... Cause rollout didn't miss.