Why does being accidental in nature make it an ill-fitting term? Suicide is not the only word to use the -cide suffix: genocide, regicide, homicide, uxoricide. The -cide suffix regards the act of killing, not of intention or purpose.
But then again the "self" prefix means doing it to yourself, as in "self-portrait" (which is where "selfie" comes from): taking a portrait of yourself.
So "selficide" would mean killing yourself, i.e. the same thing as suicide.