For task 4 on its own; I consider the 3rd task as a bit of an anomoly as it was not in Sophia's classroom. So I would consider any escalation, or even something different, from task 2, as a sexy scene, if done erotically. I want more than just flashing a different color of panties, or "there she is braless again", but some form of exhebitionismin in front of her class. After task two, it seems to me that no panties might be the logical next step. Perhaps some brief nudity; a nip slip, bending over and showing some butt, a brief pantiless upskirt. I don't expect (but would gladly accept) a wide-open pantiless upskirt on her desk for the whole class.
But we are talking about two events, the 4th task and then the bonus event. Between the two, I'm hoping for something more imaginative. But I have no predictions.