Sheldon: Leonard we need to do something about your wife.
Leonard: What's the matter?
Sheldon: She is clearly sick, and she's gonna take us all down with her.
Leonard: She's not sick, Sheldon.
Sheldon: She is, and I'm gonna catch it, and it's gonna ruin the greatest day of my life.
Leonard: I promise you're not going to get what she has.
Penny: What's going on?
Sheldon: [gasps] Unclean! Unclean!
Leonard: He thinks you're sick.
Penny: Oh. Should we tell him?
Leonard: Well, if we don't, he might try and jump out of the plane.
Penny: Yeah. Doesn't answer my question.