It seems like a gray area. Accidental Death and Dismemberment insurance generally covers death by homicide, although it can have an exclusion for homicide or dismemberment that occurs in self-defense (for example, war injuries are usually excluded). So in this particular legal sense, the "accident" can be seen as on the part of the assailant, who did not intend to be injured (regardless of their victim's intent to injure). But in general, accident is not a very well-defined term; in this case "occupational injury" may be more appropriate.
