הקורא בספר על האסקופה ונתגלגל ראש האחד מהספר מידו ונשאר ראש השני בידו גוללו אצלו אפי' נתגלגל חוץ לד' אמות ואפילו ברשות הרבים והאסקופה ברשות היחיד משום בזיון כתבי הקדש התירו: הגה דרבים דרסי על האסקופ' ודוקא כתבי הקדש אבל בשאר דברי' אסור אפי' לא נפל אלא לכרמלית [המגיד פט"ו והרשב"א]:

If someone is reading a scroll on the doorstep and one side of it rolls from his hand, but the other side stays in his hand, he can roll it back, even if it rolled outside of his four amot, even into the public domain and the doorstep is in the private domain. Because of the potential mistreatment of holy texts, this was allowed. Rema: This is because many people walk on the doorstep. This is specifically regarding holy texts, but one is forbidden to roll back other texts even if they only fell into the karmelit (HaMagid chapter 15 and Rashb"a).

If someone was reading on the roof and one side of the scroll rolled from his hand, if it hasn't reached within ten tefachim of the ground, he may roll it back. If it reached the bottom ten tefachim and the wall is slanted such that the scroll can rest on it, it is forbidden to roll it back; so that it is not mistreated, he should turn it around onto the text. If the wall is not slanted, as long as it has not reached the ground, he may roll it back.