Panel 1: Liz tells Christopher that Farley ran after she unhooked his leash and asks if he's seen him. Christopher says "Nope."
Panel 2: Liz tells him the truth as she sees it when she says that she's been looking and looking and can't find him anywhere; fungus people might say that the extend of her search is jumping angrily down a roadway with her eyes shut while holding his lead in her hands and hollering "STOOPID DOG!!!!" for fifteen solid minutes but she sees herself as having looked everywhere.
Panel 3: Christopher decides to have what turns out to be a little fun at her expense when he explains that to find a dog, one must think like a dog. Liz is skeptical about his knowing anyone like that and says so.
Panel 4: Richard stands there looking gobsmacked because he realizes that he just got drafted to play Human Bloodhound.
Summary: For some ungodly reason, Lynn loves to lump children and dogs together because they're not as fastidious as someone who furiously sweeps back steps. We're seeing here and we'll see it when they try to figure out which family member the Martian is most like.