"I was just flabbergasted," Maksim's fiancee Peta Murgatroyd told People after Monday night's elimination results were revealed.
Heather, 30, and Maksim, 37, were sent packing after they earned the first perfect score of the season on Monday night for their rumba routine, and the show also marked Maksim's highly-anticipated return to the stage following a four-week hiatus due to a calf injury he suffered during a Week 2 rehearsal.
"Maks had just come back and was so positive and really excited to be back and dancing again -- and now to just get out like that, it hurts me as much as it hurts him. I just thought they would stay," Peta continued.
"I was so bummed," added Peta's celebrity partner Nick Viall from The Bachelor. "Maks has been such a supporter of me and helping me. He was so excited to get back."
Pro dancer Sasha Farber called Heather and Maksim's elimination "nuts," especially since she was a frontrunner in the competition from the start.
"It just shows you can get perfect scores and then something like this can happen. It just puts into perspective and proves we have to be on our toes the whole time," Sasha explained to People.
Fifth Harmony member Normani Kordei, who is paired with Maksim's brother Val Chmerkovskiy this season, said, "I always have a love/hate relationship with Mondays because you can get a perfect score but at the end of the day no one is really safe. It's super unpredictable because it comes down to the fans voting. That could have been us even. But she's an amazing dancer and an amazing spirit and it's been fun."
Val called Maksim's ouster "bittersweet" because, despite their rivalry, they still want the best for each other.
"When we play pickup ball we always try and play on the same team because I want to win but I never want to see him lose," Val admitted. "But that's the nature of the show. I couldn't help him."
Iconic figure skater Nancy Kerrigan told People "it's sad to see anyone go."
"We were working as a team tonight and we spent a lot of time together... The whole thing stinks," Nancy said, referencing the "Team Dance" round in which the ladies had to perform a routine against the guys. "We were thinking with the two groups maybe they wouldn't send anyone home because they were really strong teams. It was hard."
And America's sweetheart, 20-year-old Olympic gymnast Simone Biles, also said it was tough to watch Heather leave the competition so early.
"I hugged her and said, 'We love you mom.' Because she is like our mom. If we ever need anything, she's on it," noted Biles. "She's like the leader of the group so it's sad to see her go."