How do SamnEric treat Ralph when he shows up at Castle Rock?
Ralph waited until the single guard is replaced by SamnEric and then he stealthily approached them in order to try and find out what had happened. Once he gets their attention, they are nervous and even ashamed of the fact that their faces are painted and they have joined Jack's tribe. They explain that they were forced to, even hinting that Roger did something terrible to them in order to push them to join. They make it clear that they fear Roger far more than they fear Jack.
SamnEric clearly still care about Ralph and want to help him stay alive, which is why they urge him over and over to leave. They give him some meat, clearly demonstrating their affection for him, despite the fact that they've now joined Jack's tribe.
They explain Jack's plan to hunt him down and kill him in the hopes that Ralph can somehow find a way to avoid capture. Ralph then leaves in order to try and find a place where he will be safe from Jack's hunt.