Frank had known Edward a long time, and although their past life seemed like an alternate reality at this point, he felt as if they could trust each other with anything. That’s why Frank felt so torn about keeping Phileas's secret from him. The doctor had more or less promised him that they wouldn't be hurt while they stayed there, and Frank really had no choice but to trust the cannibal at this point. Not only were they indebted him - now, they were also at his mercy.
And so, as they walked back through a spacious hall, heading to their rooms for the evening, Frank bid his friend a quiet goodnight.
"That tournament he mentioned starts tomorrow," Edward said, "are you excited to go?"
"Yeah, I suppose." Frank shrugged.
Edward looked down for a moment, and then turned to go into his bedroom.
Frank flinched. "Is something wrong, Ed?"