... an "American Idol" contestant will be sunk.

This week's challenge sounded daunting from the moment we heard about it: The final 6 had to choose from the formidable songbook of Broadway musical composer Andrew Lloyd Webber. This is the man whose smash award-winning productions include "Phantom of the Opera" and "Cats" and "Evita."

The finalists were definitely thrown out of their comfort zones, as host Ryan Seacrest promised at the top of Tuesday's show. The results ranged from downright dreadful to surprisingly good. Those who believed in what they were singing are safe ... and those who had no idea what they were doing are in peril. (Can you spell B-R-O-O-K-E?)

Donald Munro and I break down the telecast. Tell us what you thought.

Overall impressions?

Donald says: All I can say, Felicia, is that if Jason Castro had starred in the original Broadway production of "CATS," the rest of the felines in the junkyard would have risen up as a mob and torn off all his paws for what he did to "Memory." Easily the lowest point of the season, Jason's performance transcended badness and became almost endearing. It was like watching a "Saturday Night Live" sketch on a Tuesday.

Yes, it was probably a mistake to force the contestants to sing Andrew Lloyd Webber songs because the majority of the voices just weren't big enough to handle them, but I have to admit: I rather enjoyed the evening, if only because Sir Andrew as mentor was so refreshingly blunt. Instead of the wimpy approach favored by Dolly Parton and Mariah Carey , in which they basically acted as cheerleaders for the contestants and offered no meaningful advice, Sir Andrew said what he thought. I actually guffawed when he said of Brooke White's first clumsy attempt at singing "You Must Love Me": "I don't think that girl had a clue at all what that song was about." He was appalled at Jason's choice of "Memory," an entirely appropriate response, and he heroically intervened with Carly Smithson and convinced her to sing the much more appealing "Jesus Christ Superstar."

Felicia says: Besides David Cook (I'll get to him later), the other highlight for me was Sir Andrew. So, Donald, on that point, I totally agree with you. I just loved his diva-ishness. It's what I wish supreme diva Mariah Carey had provided last week. Give us some attitude. Deliver some delightfully catty lines. Demand some effort from these contestants. Don't just say how nice they all are. Sir Andrew cranked up the personality wattage, and why not? His shows are known for their grandeur, their opulence and some of modern Broadway's most memorable songs. While he had to end his observations of each finalist on an upbeat note, his candor was much appreciated. Of Jason's decision to sing the female diva song "Memory," Sir Andrew said: "I never thought I'd ever see a man sing 'Memory' wearing dreadlocks." Like you, I LOL'd at his assessment of Brooke's first audition attempt. He advised David Archuleta, twice, to open his eyes when he sings: "I can't watch someone who's got their eyes closed all the time." And I, too, loved how he correctly nixed Carly's first song choice. In one fell swoop, he recognized her weekly dismal efforts to pick the right song and directed her to a more fitting selection. Sigh. I wish Sir Andrew could stay on for the rest of the season. It would be a lot more entertaining.

Strongest performers?

Donald says: Syesha Mercado was in her element, for sure. She's always struck me more as a theater person than a pop singer. But her voice has hit a wall for me: She's adequate and nothing more. The vocal quality just isn't there. David Archuleta was adequate but no show-stopper; he is going to have to kick it up a notch beyond the inspirational-elevator-music vibe or he's outta there. My fave by far was Carly, who pepped up an already peppy "Superstar" with a strong voice and engaging stage presence.

Felicia says: I know you strongly disagree, Donald, but, for me, it's again David Cook. Instead of changing up "Music of the Night" from "Phantom," Cook sang it straight. It was emotional and showed his versatility. I totally believed him. (Sorry, Donald, but Syesha is just forgettable -- past AI winner Fantasia kept popping in my head as someone who could blast that song from "Starlight Express.") Honorable mention goes to Carly. Sure, she got a little shouty, as Simon said, but for once she looked like she was having fun. Which meant she let her beautiful voice just fly.

Weakest performers?

Donald says: David Cook reeked in an understated, one-day-past-cleaning-out-the-fridge sort of way with an insipid rendition of "Music of the Night." Not terrible, just middling: He should have skipped the Broadway style entirely and gone for his own rock spin. I can't even make fun of Brooke White because it was so painful to watch: first the false start and then the rough vocals. When you make Madonna (who sang the original song in the movie version of "Evita") sound like a trained singer, it's not a good night. Worst of all, of course, was Jason. But I have to give him points for uttering a line that will go down in "American Idol" history when commenting on his selection of "Memory": "I didn't know a cat was singing it."

Felicia says: Easily, Jason and Brooke were the most cringeworthy. Jason just looked like he was in real pain singing "Memory." I don't understand why he picked a song so strongly identified as a big-voice diva spotlighter performed by the likes of Barbra Streisand. I wrote down "this is a struggle with a capital S" moments before Simon said it. As for Brooke? She forgot the lyrics. Her singing was strained. And looking big-eyed up toward the ceiling is not acting.

So who goes home?

Donald says: Brooke, I suppose. Or Jason. Or perhaps the heavens will open and the music gods, taking pity on humankind, will descend just as the final announcement is being made and smite them both.

Felicia says: Donald, we can't have a double smiting. As much as I want Brooke to go, Jason was the worst this week with his two-minute impersonation of a musical tooth extraction.