"As good as this week was, next week is off the charts," Harrison toldTV Guide.
Monday night's broadcast left off with Kelsey Poe appearing to have a panic attack right before the Rose Ceremony. The bachelorettes were worried about their fate in the competition since Chris Soules was so sure of whom he wanted to send home he canceled the night's cocktail party.
"We deal with the rest of the attack, which leads into the Rose Ceremony, and then we quickly head to Deadwood, SD, and have a two-on-one, which we haven't seen in quite some time," the host said.
Harrison suggested the two-on-one date is going to be jam-packed with drama -- more than any prior season.
"It is the wildest, most confrontational two-on-one we've ever had. I go back to Andy Baldwin's season when [Peyton Wright] was left on the runway. That was emotional, but this is a different level," Harrison explained, referencing how Wright had been standing on the deck of the USS Midway as The Bachelor: Officer and a Gentleman star took off in a helicopter with another woman.
The upcoming two-on-one date will apparently be much more intense than this week's group date in which previously-eliminated bachelorette Jordan Branch surprised Soules with her return and attempted to rejoin the cast.
"I got a head's up she was going to show, so I knew," Harrison said of Branch's six-hour car ride to Santa Fe.
"But the problem was it's a no-win situation for Chris. The girl drives all the way from Colorado and throws herself at the mercy of the court -- What's he supposed to do? She was very apologetic and it was hard to not bring her in for at least the party. But I clearly understood why the girls felt three weeks later she doesn't deserve to be here now."
Harrison said Soules would've "seemed rude" if he had thanked Branch for showing up but then just instructed her to get back in her car.
"So, I think he handled it well, gave her a shot, but said, 'This isn't going to work,'" Harrison continued. "Even if she deserved more time, there was no way he was going to lose the house."
The house was fairly torn over Branch's decision to come back and fight for Soules again. Whitney Bischoff and Ashley Iaconetti argued, for example, because Bischoff didn't want to say anything bad about Branch nor did she blame the Bachelor for whatever choice he wanted to make. On the other hand, Iaconetti was pissed off and jealous.
"[Whitney] is very quietly flying under the radar. She has a little dust-up with Ashley, but everyone does -- the drama that is Ashley's life is bigger than any soap opera. But Whitney is mature, and I think she is able to handle all of these situations and emotions better than some of the other women, which puts Chris at ease," the host told TV Guide.
"The other women were freaking out about Jordan -- Ashley was ready to get a posse together and string her up. While Whitney didn't love it, she articulated it much better... This group is catty. I don't know if it's fair to label them as immature; I don't think it's as simple as that. I think it's a competition thing and a jealousy thing more than ever because the battle for Chris' heart is more intense. But, yeah, it's a very catty season."
The Bachelor's next episode airs Monday, February 9 at 8PM ET/PT on ABC.