Question

Have a good week, Rabbi,
Some time ago you taught us that there is no need to have specific intent when refraining from a prohibition. I came across a passage in tractate Kiddushin that seems, on the face of it, to contradict that:
Kiddushin 39b
Rav Tuvi bar Rav Kisna raised a contradiction to Rava: We learned in the Mishnah: “Whoever performs one commandment, good is done for him.” If he performed one, yes; if he did not perform one, no. But this is contradicted by the teaching: If one sat and did not commit a sin, he is given reward as though he performed a commandment! He said to him: There, it is referring to a case where an opportunity to commit a sin came to his hand and he was saved from it. Like the case of Rabbi Hanina bar Pappi, whom a certain noblewoman propositioned. He uttered something and became covered with boils and sores. She did something and he was healed. He fled and hid in a bathhouse, where even if two people entered it, even by day, they would be harmed;
This is also difficult for the principle that a positive commandment overrides a prohibition, because if refraining from a prohibition is equivalent to fulfilling a positive commandment, then by simple calculation it would be preferable to refrain from violating the prohibition and neglect the positive commandment (and incidentally thereby fulfill another positive commandment, namely refraining from the prohibition), rather than fulfill the positive commandment and violate the prohibition.
Best regards,