They use a Palm Pilot as a "firefly" and start squirting people's hands. They don't find anyone. The Inspector admits that it was an "inspired" effort, and then he asks the stewardess to "raise the lights." But wait! John's got to squirt the inspector's hands. There's blood all over them! The audience erupts into a world of "ohs!" and "ahs!" The inspector screams, "I'm not the killer!" Then he squirts the rest of his clothes and explains that he moved the co-pilot's arm, and that's where the blood came from. Then he squirts John's hands, which also have blood on them from when Rachel removed the poison. The stewardess turns the lights back on. John asks, "Are you sure this is everyone?" The stewardess replies, "Yes. Except -- I think someone is missing!" They check the manifest again, and sure enough, they find that Louis Garber, the aeronautical engineer, is indeed missing.
John immediately goes to check on Rachel. When he gets back to the rear of the plane, he discovers that Pavel's been knocked out cold.
Louis and Rachel struggle in the hold. He's opened some hatches, and this is causing the oxygen to deplete. Wind whips them all over the place. Rachel screams, "Please. Why are you doing this to me?" Are you ready for it? Are you sure you can handle the cheese? Are you sure you wouldn't like a laxative before we begin? Okay. Louis's mother died of the very disease Rachel treats. Only Rachel wouldn't let her into the study. She didn't think his mother would make a good candidate. As Rachel screams, Louis shouts out the whole story. He screams, "I want you to suffer like she suffered." As a result of Rachel's rejection, his mother died. Rachel screamed, "That was three years ago!" Yes, but the maniacal mind of Louis waited in the wings for the perfect moment to "get" to Rachel. Now, he's got her on "his" turf. In "his" world, the world where he controls her death just like she controlled his mother's three years ago. John comes down the hatch and sneaks up on the killer. Louis busts open a flare and threatens to light up the cockpit oxygen if John comes any further. John screams, "Let her go!" Louis shouts, "I'll let her go when she's dead!" Then he takes a good lungful of oxygen just to prove that he can breathe while Rachel starts to choke. John tries to reason with him, but Louis just won't listen. John has no choice -- he's got to unleash a luggage compartment on the poor dude, squishing him, and therefore taking him out of commission. Aw, my hero. Yawn.