What I found most striking about this episode was how it combined outpourings of extremely wrenching emotions with typical MITM tongue-in-cheek irony. I can't think of a more gripping moment than when Lois realizes her disaster of a son, Reese, is an extension of her--"I am you!" She seems devastated--"All I can say is, I'm sorry. I'm deeply, deeply sorry!" And then the mood-jolting ironic twist: Reese: "There's one left?" The marvel of this episode is that the irony, the mockery of the characters' feelings, in no way lessens the story's emotional power. When Malcolm is at its best, as it is here, it ridicules and empathizes with its characters all at the same time.
Lois is portrayed as having two conflicting sides to her personality: She is a brutal vindictive savage and she is a strict moralist. The savage side is all Ida. The moralist side is her rejection of Ida's raw savagery as unfit for a civilized society and her embracing of strict respect for rules and for authority as necessary for civilized life. Here she first goes to the accepted authority figure, the school principal, who clearly intends to do nothing and rather enjoys Reese's misery. This unleashes the savage in Lois, and she goes on a vindictive rampage that would make Ida proud. What finally reawakens her moralism is the realization that she was enjoying her vengeance too much: "I enjoyed crushing those girls and watching them suffer. I tapped into some dark ugly place inside me." That place is the primal bloodlust of the savage who after killing his enemy cuts off his head and hangs it as a trophy. It's also the part of her personality that she passed on to Reese.
The notion that Reese's savagery is just an extension of Lois' is reinforced by the incident that triggers Lois' sense of shame: she frames a perfectly innnocent boy to take the blame for her own mischief, exactly what Reese did in his most wickedly callous escapade, the "evil twin" scheme ("Forbidden Girlfriend"). The difference is that Reese has none of Lois's moralism, so he never sufferered from pangs of conscience.
That moralism all went to Malcolm. Lois isn't just Reese. She's also Malcolm, and throughout this story Malcolm shows himself to be the other, moralistic half of Lois' personality, the part that rejected Ida's brutality. This theme has been around throughout the whole series, as Ida has always despised Malcolm as an over-thinking twit and saw Reese as the family's only hope.
Hal's story completes the circle by showing why Malcolm and Reese's characters have been shaped entirely by Lois. Hal wants no part of getting in the way of Lois' rage. He's terrified of her. He thinks up all kinds of pretexts for rejecting Malcolm's plea that he do something to stop Lois. Instead of playing a father's role, he retreats into a boy's make-believe world, fantasizing that he's a major league ballplayer. As has often been shown in many episodes, Hal is more of a pal and playmate than a father. Lois is the only real parent, and her boys' characters are entirely reflections of the different parts of her personality.
Some side tidbits:
--The pig looked familiar. He looked just like Ralph, the pig who shared Francis and Piama's bed in one of the ranch episodes (can't remember which.) If I'm right, this is the second encore appearance by an animal this season, the first being the return of "Dewey's Dog" Marshmellow in "Bride of Ida."
--In the sponge bath scene, the caulking in the bathtub is grimy with mildew. This little detail is part of what gives this show the sense that we are seeing the real house of a real family, rather than the set of a tv show. It's yukky, but very effective.