"I actually just screened the finale, and it's insane. It's like nothing we've ever seen, and that's speaking after [Arie Luyendyk Jr.]'s, which was like nothing we've ever seen," Mills toldEntertainment Tonight.
Shortly after getting engaged to Becca Kufrin, Arie realized he was still in love with his runner-up, Lauren Burnham. He therefore dumped Becca after several weeks together in early January and begged Lauren to take him back.
Thankfully, things worked out for the pro racing driver and now he's expecting his first child with Lauren, whom he married on January 12 in Hawaii.
"The lesson is always that you have to let it play out real... We still have to fill 20-something hours of television, but we've always been rewarded when we've let it play out and not as a game where there are rules that have to be stuck to," Mills explained.
"This finale is so different and things really do go so off the rails that it's important for us, for the audience, to let it play out for them."
As fans may recall, Mesnick had a change of heart and dumped his fiancee Melissa Rycroft for his runner-up Molly Malaney on The Bachelor: After the Final Rose, Galavis gave a rose -- but no ring -- to his winner Nikki Ferrell without even professing his love at the Final Rose Ceremony, and Womack rejected both of his Final 2 women at the end of his first stint on the show.
"We finished filming in November, right around Thanksgiving... In this case, we're going to make the finale two nights. There's a cliffhanger Monday night, and Tuesday night it will get paid off," Mills shared with ET.
The Bachelor is heading into its seventh episode on February 18, and only seven bachelorettes remain in the running for Colton's heart.