If he became unclean in the Temple Court [and was aware of it], and the uncleanness then became hidden from him, though he remembered the Temple; [or, the fact that it was] the Temple became hidden from him, though he remembered the uncleanness; [or,] both became hidden from him, and he prostrated himself, or tarried the period of prostration, or went out the longer way, he is liable; the shorter way, he is not liable; this is the positive precept concerning the Temple for which they [the Beth Din] are not liable.

שבועות 2.3
נטמא בעזרה, ונעלמה ממנו טומאה וזכור למקדש, נעלם ממנו מקדש וזכור לטומאה, נעלמו ממנו זה וזה-- השתחווה או ששהה כדי השתחוויה, ובא לו בארוכה-- חייב; בקצרה, פטור׃ זו היא מצות עשה שבמקדש, שאין חייבין עליה.

And which is the positive precept concerning a menstruous woman for which they are liable? [this:] if one cohabited with a clean woman, and she said to him: `I have become unclean!`; and he withdrew immediately, he is liable, because his withdrawal is as pleasant to him as his entry.

 שבועות 2.4
איזו היא מצות עשה שבנידה שחייבין עליה׃ היה משמש עם הטהורה, ואמרה לו נטמאתי-- פירש מיד, חייב׃ שיציאתו הניה לו כביאתו.