I do agree that logically, it makes more sense to show it now. But how many viewers really care about that family? Their deaths aren't midseason cliffhanger worthy IMO. I'd forget about them by February.And this might happen in the mid season premiere but idk why they would wait until then to show it when it would be more effective now.If I remember correctly. Rick, Carl, the mom, and the kid are walking out holding hands like they are now. The kid draws the attention of the zombies and gets caught. He's holding Carl's hand and refuses to let him go. Rick decides to cut the kids arm off to save Carl.
Edit: it was the mom who was holding on to Carl and Rick cut off her arm.
I think they're gonna drag out the storyline of "Rick" getting more people killed based on this scene.