Harrison said the pain of Cassie's sudden and unexpected decision to quit the show hit Colton even harder because he was anticipating having sex for the first time with her in the Fantasy Suite that night in Portugal.
"He thought he was about to have the night of his life. He finally was going to -- no pun intended, or maybe it is -- put this to bed and put this whole thing to rest," Harrison said.
"And now it is, 'How do we really get him back?' And that took a very serious conversation the next morning."
Harrison said Colton had producers thinking, "Let's see if we still have a show."
Once Cassie crushed Colton's heart and left him with Hannah Godwin and Tayshia Adams, Colton shoved a camera out of his face, ripped off his microphone, jumped a fence, and threatened to end production.
"We lost him and the show. We were discussing having to call the authorities. That was our next step... He was emotional, upset, pissed off, mad at production, mad at me, mad at himself. Everything was just pouring out of him," Harrison recalled.
Harrison revealed, "The only thing I knew was we have to take care of Tayshia and Hannah G. -- we have to let them know."
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When asked whether Colton felt The Bachelor had let him down, Harrison said on GMA that Colton felt "a little anger and animosity" towards the show.
"And I think there was a little miscommunication. We are only there to facilitate him finding love, especially at the end of the show," Colton insisted.
Considering Hannah G. and Tayshia are still in the running for Colton's heart but he so clearly loved Cassie, GMA asked Harrison whether Colton was misleading when it came to his feelings.
"I think he was so scared," Harrison explained.
"I think he loved Cassie so much and I think he was so scared, and maybe it was kind of self-manifested in that you end up trying to protect something and save it so much that you end up bringing it to be."
Fans will find out how Colton's journey to find lasting, mutual love ended during The Bachelor's Season 23 two-night finale event on Monday and Tuesday at 8PM ET/PT on ABC.