I say, and with God's success: The limit of leaving the mosque is the separation of his feet; this is to avoid the case where his head exits to his home, as it does not invalidate his I'tikaf; because it is not considered leaving, just as if he swore that he would not leave the house, and he did that, he would not break his oath; as narrated by Aisha, may Allah be pleased with her: “The Messenger of Allah (peace be upon him) would bring his head close to me while I was in my room, and I would comb his hair while I was menstruating” in Sahih Muslim 1: 244.