Imagine, as a random event, the game will select one person who has event preference set to either kill, eat, or kidnap (hereafter called the target), and one person who has set themselves as an event volunteer (called the volunteer). It will then grab the target's OOC Notes, and show them to the volunteer, and ask if they are compatible. If the volunteer says yes, it will then show them the preference they set (kill/eat/kidnap) and ask if they want to become an antagonist with this objective. If yes, then they are automatically assigned as an antagonist.
What if the target is already in a scene or otherwise occupied?
Well, you could possibly give them a notification box asking if they are willing to be a possible target when the event happens, not even asking the volunteer about them if they say no, and instead trying to grab someone else who has set their event preference for targeting. Or, at the most simple, the volunteer could ask the admins to de-antag them if the target is already in a scene.
What if the volunteer agrees to someone whose prefs are very much not compatible and tries to force them into a scene?
Again, the admins could be brought in since this is direct breaking of the station OOC rules.
I believe this system would encourage people to find scenes, let people get scenes they may not otherwise have gotten, and possibly even help break up cliques by convincing preds to go after people other than their usual prey.
I will edit this (and mark edits) as feedback is given.