“why do you think that you can disagree with the Gemara? you do not know why the doctor was allowed lechatchila (as opposed to being driven by a goy) or why the rav thought that he could hitch.”
First: You certainly cannot paskin or bring proof just from a g’mara, as you have done, but as we see many times in the g’mara when there is a disagreement, a maeise Rav has precedence. There is also a flip side to this: ?”? ????? ?”? ??? ?”? ????? ??? ??? ???? ??’ ????? ?? ????? ??? ??? ?’ ??? ???? ????? ???? ??????? ?? ??? ???? ????? ??? ??? ???? ??.
However, being that both the doctor and Rav were ehrlich and talmedei chachomim; I don’t need to know any more. Perhaps since the doctor could come back l’chatchilla; the Rav may have been allowed to go with him. Maybe in a different situation, the Rav would not have done it. I don’t know nor do I care. I do know that in this situation, I would do the same since to me a maeise Rav carries weight whether l’kula or l’chumra. BTW, the Rav is not a kula type individual.