[He's immediately sobering up when he mentions Grell's name, if only because she's someone he likes well enough. It's questionable to think on why she would think she wasn't real, though Luke himself has been struggling with that question for an entirely different reason. He's listening to the story and he's confused, slightly, but he's nodding in agreement anyway.]

Grell also hadn't believed we were really in space, though she might be more on track than we originally thought if Alice can't connect us to anything. You're concerned other people will react the same way. Be reckless if they think we aren't real? Could cause a mass panic and even escalate the murder game that way.