“NEVER AGAIN NEVER TRUST WE FIRST, ALWAYS.” The mantras painted onto the walls of a makeshift, candlelit memorial chapel were not exactly hospitable. As it turned out, Terminus was not quite the sanctuary that the straggling survivors of “The Walking Dead” expected.

Season 4 of this dystopian action-adventure series on AMC ended on Sunday without revealing what was wrong with Terminus, the smugly self-sufficient community that lured the heroes to a train-yard enclave with promises of peace and safety. The friendly welcome cooled off fast: At episode’s end, they were left locked up in a boxcar, awaiting an unknown fate.

Over four seasons, these survivors have faced every kind of horror and twisted form of savagery. So it is only a question of time before the show taps into cannibalism.

Nothing is made clear about what happens next, but as is so often the case with “The Walking Dead,” one thing is certain: Humans are a greater menace than the zombies who took over the world and brought civilization to its knees. Everything is gone: law, order, money, farms, shops, highways, schools, hospitals, civility and trust. Killing isn’t a choice, it’s a survival skill. The heroes question themselves on whether they had a good enough reason.