Can someone tell me how this VQ died?

[ioticus]

sushiboat said:
Yes, I saw the turn. It was a long battle, so I may have missed a crucial moment. It was difficult to see the VQ with all the fire shields and astral shields of the other mages.

As far as I know, heat damage doesn't cause fatigue. I guess that the fatigue came from the VQ's own spells. Earlier I did see Caelum cast Thunder Strike, which does cause fatigue.

I've watched the battle many times, and the VQ wasn't casting spells when her fatigue suddenly started to quickly increase.