Warning: This post contains spoilers for part 1 of Bridgerton season 4.

There’s a lot of work still to be done if Benedict Bridgerton is serious about Sophie Baek.

In the final episode of Bridgerton season 4, part 1, Benedict (Luke Thompson) asked Sophie (Yerin Ha) to be his mistress — a question that arose in the middle of the pair’s steamiest moment yet. Sophie’s heartbreak at the ask was written all over her face, and she ran off from the second son without giving him an answer.

Ha, 28, tells PEOPLE she was “also pissed off” herself, as an actress during the scene, given the disrespect of Benedict’s request, and she breaks down what that tense moment means for part 2, which drops Feb. 26.

“I think in that moment, when the spark happens, she kind of crumbles and lets all her walls down,” Ha says of the staircase hookup between Sophie and Benedict. “But the minute he asks the question, the walls immediately go back up.”

Part 2, then, is “another adventure of, how is he actually going to break her walls down and make her feel vulnerable?”

“If anything, [Benedict’s offer] actually makes her more strong-headed and scared to open herself up again,” Ha continues. “So it’s almost like he’s undone all the hard work that he’s done in part 1.”

Benedict’s hurtful offer aside, Ha said the sexy moment for her character and Thompson’s is “quite poetic,” as are all steamy scenes in Bridgerton.

“They don’t feel like they’re there just for the sake of it. They’re actually an extension of the storytelling,” she said.

That is “especially” true of the staircase scene, she said, given the scene’s “upstairs-downstairs” symbolism. “It is like, what does that represent and what story are we trying to say in that moment exactly?”

“I do think Bridgerton does the sex scene so well in terms of, from a female gaze,” she added. “And when you have trust with a great scene partner like Luke, it always just comes together quite naturally.”

Speaking to her chemistry with Thompson, 37, Ha told PEOPLE that she was most nervous to meet him, given she “had to play lovers with him,” but they clicked really quickly.

“[I] just wanted to really make sure that our dynamic was good — not that I was going to force anything — but you just kind of hope and pray that it will just be a nice, easy transaction, and it really was,” she said. “So I’m very fortunate for that.”

Bridgerton season 4 is a Cinderella love story, as Benedict meets a mysterious Lady in Silver at his mother’s masquerade ball and sets out to discover the woman’s identity, completely unaware that Sophie, the intelligent maid he’s since met, is who he’s been searching for all along.

At the same time, new challenges arise for his married siblings, Francesca (Hannah Dodd) and John Stirling (Victor Alli) and Colin (Luke Newton) to Penelope (Nicola Coughlan).

Part 1 of Bridgerton season 4 is now streaming on Netflix. Part 2 premieres Feb. 26.