'Zerker actually has an easier time of it than most melee classes. Pick up rush (you should have had at least a point in it already, possibly more than one), a movement infusion, and possibly a set or two of boots of rushing. The timer goes up a bit each time you kill one of the cultists, so as long as you can get to them and lock 'em down (Rush -> Stunning blow. If they're not dead already, another hit or two will probably do them in) you'll do pretty well. A slime weapon wouldn't hurt.
I've saved melinda a few times now, since tac AI started having casters back off from melee threats. As long as you've got adequate movement capability (1-2 movement infusions and rush, possibly double rush or better -- talent+boots, possibly some boots on swap) you should be alright. Just realize that if you're not a class with hefty burst damage (Fighter, sunpa, possibly cursed, can lack a bit here. Wyrmic has some decent ranged capability and lightning speed. Reaver, brawler, TW, slayer shred the cultists once you get beside 'em.) you're going to be cutting it close.
Still. Bring plenty of movement aids and you'll probably be fine. Worst comes to worst, failing to save Melinda is about as good an outcome as managing it. Saving her tends to get you somewhat better loot, but failing gets decent-enough loot and XP. It's win-win, really.