I completely agree with you. I think this is one of the most interesting points in the upcoming event. It could be a pivotal moment for the story if Sophia, despite her intentions to draw the line, give in once again and this time she becomes more active role in the scene. That would the closest she goes to cheating to this point.
As you said, so far she has been "passive" in most of the scenes, even when she gave in she rarely went further taking some initiative. And even with the apostles it was still in the range of the sex-ed, she didn't act driven by sexual desire or anything.
I think the only instances where she took an unsolicited initiative is when she teased the boys at breakfast and Sam during the basketball break. I guess we can also count spying on Nathalie even though there was not much interaction there.
Chronologically, I think the situations where she took **some kind of initiative** during the interaction with other characters are
Day 4 - First time spying on Nathalie but not much interaction.
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Day 16 - Teasing Sam and Dylan at breakfast. There she took the initiative without even being solicited
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Day 16 - Showing the areolas to Sam. She kinda took the initiative even thought it was more another take of the sex-ed cliché
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Day 16 - Teasing sam when he came inside the house during the basketball match. Again, without being put in the situation it was all her initiative
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Day 16 - Flirting with Morello at the casino. Nothing much happening but she openly flirt back.
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Day 17 - Spying on Nathalie the second time, again not much of interaction though.
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Day 17 - Asking Zac to help with the lotion, but there was no ulterior motive there.
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Day 18 - After being dragged in the erotic game by Ellie and Julia she took the initiative to bare Julia's breasts
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Day 19 - Giving a bonus to Larry at the end showing her panties. Although she was kind of "forced" to interact with Larry and satisfy his demands, this last part it's probably the very first time Sophia took an initiative with another character going beyond some innocent teasing and flirting
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Day 19 - Playing with Patricia while dancing. This is maybe a bit of a stretch as she just doubling down the game started by Patricia.
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Day 19 - Giving in during the kiss with Sam, she becomes more involved in the kiss and she embraces Sam. Again not much, but a little sign that she wanted to give in and she is not just passive at that moment.
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