Are you referring to the first or the second Insight on that daf? What are the first five words of the paragraph?

If you mean the Rashba's answer to the third question that we asked in our second Insight, what he says is as follows. According to Rebbi Yosi (Hav'arah l'Lav Yatzas) - Had the Torah not disallowed Hav'arah for killing in Beis Din on Shabbos, we would have allowed Beis Din to light the fire (Aseh Docheh Lo Sa'aseh), and then told a non-Jew to use the melted metal to kill the Bas Cohen (since Aseh is not Dochech a Lo Sa'aseh that has Kares). The verse thus tells us that this is not allowed.

Best wishes,

M. Kornfeld

Kollel Iyun Hadaf