Once you have 7 Silent or above kills or stuns in a row without dying, you can select any player to kill in an instant - to others am I right?
Yeah, pretty much. 7 silent or better quality kills/stuns or the 9 kill streak of any kill/stun will get you the animus hack. If I'm not mistaken, it's supposed to last around 30 seconds after it activates. In FFA modes, you can kill any other personas, even if they are not your target. You can also kill any pursuers you have obviously. In DM, this can bag you quite a few hack kills, since there are no copies of anyone, so you can just kill anyone that isn't one of the two personas that are swarming the map (unless they are disguised and not being obvious or are hiding from you around walls or other barriers) In team modes like Manhunt or CC, if you get the streaks purely through stuns on defense, you can kill all of your pursuers, which is pretty amusing.