a different solution for Karl
We all know he won't last long, per the show's pattern, so I won't even go into that. And I'm guessing it's definitely likelier he'll die than just, go away, like some do.
Now, my thoughts on this are out there, but it's an out-there show, and would at least be a break from the usual pattern.
Have it turn out that the main characters already know who Karl really is. Just say there was a special that aired about him on TV or something in the two years between his confinement and the outbreak. He's not in the outside world, he'd be unaware of these things. Or that they even stumbled upon his file before/after releasing him. Something.
And then all of Karl's time with them, they know the truth, and they're playing/trapping him. Like if he hadn't left the room from painting Gail (and thank goodness the mid-season cliffhanger wasn't her in mortal peril again), she could've turned the tables and attacked him or something.
Of course then there'd be the question of whether to play it for laughs, or play it straight, like a dramatic self-preservation/defense thing. Because if our core group became the way of planning a man's death like that, we'd have to see that a few screws are loose that they're at this place.
Of course this can be undone by the fact that there was the scene of Tandy and Todd watching surprised as Karl cannibalized a corpse. But this show isn't overly serious, could get around that.
I know it's a hazy idea with a few holes, just think it'd make for a nice change of pace at least.