Erik's mouth - mentioned often, but then he doesn't realize how expressive he actually is, generally; the light color of his eyes means that's where most of the feeling in his face ends up - doesn't twitch so much this time as curl, flattening out to paleness at the corners. "It does."

Another man might run his hands through his hair, or shift his stance from one foot to the other, but as Charles has correctly recognized this is Erik getting ready to stand his ground, and that means that he doesn't move. There's no gesturing with the span of his hands, his arms stay crossed and his feet stay planted. "They've worked out some kind of rudimentary bartering system. Clothes of a certain size, cigarettes. Whatever sundries."

Cigarettes sound appealing, frankly; he has something of a nicotine withdrawal headache starting, but those aren't as high on the ladder as food. He'll worry about creature comforts when he can be sure literal starvation is no longer on the table. "And there are the drop-offs, but we can't afford to rely on those."

As a scientist Charles must be aware of all sorts of experiments where animals are starved to see how long they can last before turning on one another; it's an argument Erik doesn't need to make. "The sustainability of living off the land comes to mind as well, but when dealing with our fellow prisoners--I'll handle it. It won't be necessary for you to trouble yourself."

Again: this is not a question.