I was at full health when it killed me instantly. It also one-shorted another guildmate a second before. This has happened a few other times to other guild mates.
Spoon-no-Soup Former Emperor Argonian Templar AD BWB
Spoon-ware-Soup Former Emperor Argonian Stamplar AD Bahlokdaan
Guild Leader Imperium of the Eagle Ravenwatch NA-PC