User blog comment:Zexia0053/Understanding Extra Skills/@comment-64.50.247.40-20150828214415/@comment-26297531-20150828215228

i've found out from somewhere in reddit that she (and other angel idol ES units like Ultor), can still die if the first hit wipes her hp down in 1 shot. the angel idol es only triggers if she falls below 20%. usually enemies need multiple hits (within their single normal atk, for example) to bring her down to trigger the ES mid attack (if she's taking the brunt), so that by the end of the attack she can survive with the angel idol effect. however, if the first hit crits and straight up bring her down to 0, there's no way for the ES to trigger for the rest of the hits.