I just read Nick's list of powers in her Hadriel app -- she can cause rain within a 1-mile radius of herself?

And I'm guessing that the murdercave is probably something like 6 miles in diameter at its widest? -- or more? -- just a guess from considering the features on the locations map.

If that's the case, then Nick would have to move around to put out fires, kind of the way the firefighters will. She wouldn't be able to put them all out at once, so it doesn't so much matter how soon she enters the fray.

Btw, would she be interested in formally joining the Fire Brigade?