Joe held Rick at gunpoint, and the rest of the bunch grabbed Carl and Michonne. Rick was seconds away from death when Daryl Dixon (Norman Reedus), who had been with Joe and his crew, spoke up and declared Michonne, Rick, and Carl “good people”. Unfortunately for Daryl, his last ditch effort to save his pal backfired when Joe’s group turned on him and beat him to a pulp.
When Rick saw they had Carl and were hurting him with the intent to kill, something inside of our former cop snapped. He jerked back and bit Joe’s throat, killing him and horrifying everyone else. Even himself. The shock was enough for Daryl and Michonne to turn the tables and shoot their captors, effectively eliminating the marauders. Rick was sure to give the one holding Carl an especially slow death.
The following morning Daryl, Michonne, Rick, and Carl headed for and ultimately reached Terminus, each recalling how they are now “monsters”.