Reference for Bava Kamma 52:5
רשב"ג אומר (שמות כא, כו) ושיחתה עד שיתכוין לשחתה
If the person, however, had at some time been aware of the stone in his bosom but subsequently forgot all about it, so that when he rose it fell down, — in the case of damage there is liability for Depreciation;<span class="x" onmousemove="('comment',' For Man is Mu'ad to pay Depreciation even for damage done while asleep. ');"><sup>15</sup></span> but though the exemption regarding the [additional] Four Items still holds good,<span class="x" onmousemove="('comment',' On account of the absence of a will to do damage. ');"><sup>16</sup></span> in the case of manslaughter<span class="x" onmousemove="('comment',' I.e., if when the stone fell down, it killed a human being; v. Num. XXXV, 9-34. ');"><sup>17</sup></span> he will have to flee [to a city of refuge], for Scripture says, at unawares,<span class="x" onmousemove="('comment',' Num. XXXV, 11, 15. ');"><sup>18</sup></span>