Responsa for Gittin 145:12

איגלגל מילתא ומטא לקמיה דרבא אמר להו אונסא דלא שכיח הוא איתיביה רבינא לרבא אם לא אעמוד מחולי זה ונפל עליו בית או הכישו נחש ה"ז גט

and the matter was at last laid before Raba, who said, it is an exceptional kind of accident. Rabina raised [the following] objection against Raba: '[Where he said] If I do not get up from this illness, and the house fell on him or a serpent bit him, this is a Get'? — Raba replied: Why do you not quote the earlier clause, where it says, 'It is no Get'? — Said R. Aha from Difti to Rabina: Because the first clause conflicts with the second, may we not raise an objection from the latter? — He replied: That is so; since the first clause conflicts with the second, the latter was not discussed in the <i>Beth Hamidrash</i>, and it is not authentic. [You must therefore] follow your own reason.<span class="x" onmousemove="('comment',' Which would tell you that he did not have such an exceptional accident in his mind. ');">¹¹</span>

Teshuvot Maharam