Logically, most of the lethal kill methods should be doable on a subdued person. There is no logistical reason why 47 wouldn’t be able to slit someone’s throat, stab them with a syringe or garrote someone if they were laying prone instead of standing up, but the mechanics of the game just don’t allow it.
Jumping doesn’t exist in the game (or the entire franchise for that matter), but syringe kills do.
Right now, if I accentially subdue someone, and I don’t want to restart the level, I have to make someone find the body to wake them up, so I can stab them with the syringe - say if the level requires a lethal syringe kill (take the latest Pride escalation for instance).
Furthermore, this mechanic already exists in the Hitman franchise. In Blood Money you could stab an unconcious target with a syringe, so it’s not as far fetched as say… jumping.
I’d be fine with it not counting as an accident kill since forensics could probably tell that the victim was strangled first or something like that, but it should be possible.
That would defeat most of the purpose and also doesn’t really make sense. To that logic, electrecuting a subdueded person also wouldn’t be an accident, neither a Fall.