it is not al‑wājib al‑muʿayyan]...

it is not al‑wājib al‑muʿayyan], the obligation to refrain from these things – apart from having sexual intercourse – is based on obligatory precaution. Miscellaneous Rulings on Iʿtikāf Ruling 7: When one makes the intention to perform an Iʿtikāf that is not an assigned obligation, he can stipulate a condition from the outset that if a problem arises, he will leave the Iʿtikāf.

Therefore, by stipulating such a condition, one can leave the Iʿtikāf if a problem arises, and there is no problem in doing so even on the third day. However, if a muʿtakif stipulates a condition that he will stop his Iʿtikāf even if no particular reason arises, the validity of such a condition is problematic [i.e. based on obligatory precaution, it is not a valid condition].…