After last week’s hour-long tease of Uma Thurman’s Smash guest-star appearance — which proved to amount to a cameo more brief than the friendship of Julie Taymor and Bono — this week’s Thurman-palooza proved she fit right in to this series. Which is to say, just like nearly every other character in Smash, her behavior and motives altered from scene to scene; they should call this show Schizo!

Thurman’s Rebecca Duvall commenced the night a self-absorbed brat who sang brazenly off-key and wanted less “singing and dancing” in this musical, and ended it by agreeing that nearly every musical number was just dandy as-is, and that she’d get a vocal coach. In between, Thurman played a kind of ur-Uma version of herself when the Bombshell cast went to a screening of her new thriller Casual Friday 2, a dreadful looking thriller whose first iteration Tom claimed to have sincerely loved.

Speaking of Tom and sincerity, he had a date with Sam that was halted by the latter after a single smooch — it seems the “chorus crush” “believes in God” and wants to take things slowly, because he believes sex is “holy.” (Christian Borle, who just opened to glowing reviews on the “real” Broadway in Peter and the Starcatcher, must have a difficult time getting through these scenes without rolling his eyes. ) Give Smash credit for not quite sneering at Sam’s belief system, even if that twist did seem Smash‘s umpteenth way of keeping any possible plot from moving forward. It was yet another delaying tactic in moving the narrative along in this series. We know going into this guest arc Thurman isn’t going to really stick around (she’s signed for five episodes, which apparently includes last week’s walk-on). Just as we knew, in the past, that Julia’s affair would not last, and that Eileen is going to raise the money for Bombshell (at least she gets to down dirty martinis while waiting around for the cash; all I consume are Cheetos as I watch). It’s as though going over the same ground week after week did not matter to show creator Theresa Rebeck, who seemed to approach each episode as a mere variation on the preceding week — the TV series itself is an up-and-running Broadway production not to be tinkered with once it started.

Derek had another hallucination in mid-sentence with Karen, who morphed into a Marilyn Monroe singing “Our Day Will Come,” the 1960s hit by Ruby and the Romantics rearranged to a semi-reggae beat in order to prove that Katharine McPhee can’t even wiggle in time to a beat. Karen also had a tough time with Dev. Again.

Julia heaped more guilt upon herself for her affair in not one but two scenes, thus giving Brian D’Arcy James’ Frank time to practice his not-eye-rolling. And just after Ellis told Eileen that no one was allowed in to a “closed set” rehearsal, Ellis strolled into the rehearsal right behind Eileen and no one even raised an eyebrow.

Were you wowed by Thurman’s take on “Dig Deep”? It seemed as though she acquitted herself well, though frankly I wouldn’t recognize a good Broadway show-stopper if it rolled over me, not when I’m hearing lyrics like “We’re just nuts about Sigmund Freud!,” which I know is exactly the kind of wordplay that Broadway-musical fans enjoy. All in all, it was another hypnotizing hour of Smash, the bad show I cannot get enough of. I am truly sorry to hear there are only three episodes left this season.

By the way, has anyone else read the source book for this series, Garson Kanin’s 1980 novel Smash? I confess, I could barely finish it, but read enough to be able to say, TV-Smash 1,000 times better than book-Smash. Pee-yew…

Twitter: @kentucker