EXCLUSIVE: Abby Lee Miller Drives Girls to Dark Place in 'Dance Moms' Summer Finale

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While the girls are preparing for nationals, Abby Lee Miller is opening her new studio, putting tensions at an all-time high on tonight's summer finale of Dance Moms, and ET has an exclusive clip!

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"The group number -- it's more than a dance routine," Miller says in the video. "I would call it a piece. There's an emotional range. There's interaction between the dancers. Maddie [Ziegler] is playing our lead. It's heavy. Can she pull it off? Let's hope so, because she's the only choice I have."

When the girls aren't meeting Miller's expectations for the emotional "Waiting Room" piece, she asks them to draw on the darkest thoughts that they can think of.

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"Imagine if your family -- your loved ones -- were brought in by ambulance from a car accident," Miller said. "Imagine waiting to hear the news. Is it happy news or is it the worst humanly possible news?"

No question, the girls will have to dig deep to bring out the type of performance Miller is looking for, but will it be enough? Find out when Dance Moms airs tonight at 9 p.m. ET/PT on Lifetime.