The whole group was on a mission to find Negan after they found out what happened to you, and you were more than happy to tag along, just to get some payback. Carl and you were pretty close, so he tagged along as well.

After getting separated because of a horde of walkers, Carl and the others tried to find you. They weren't about to lose you, not again. Carl especially, he was focused on finding you, so focused that he had gotten him and the others surrounded by walkers.

Just when he thought he was about to have to fight them, bullets came raining down, the walkers getting shot in the head one by one. He followed where the bullets were coming from to see you. And boy was he happy.