פירוש על עבודה זרה 55:12

There are two versions of what types of wounds should not be healed by a non-Jew. The first is the type of wound that may be healed on Shabbat—meaning a life-threatening one. The second is an internal wound.

R. Abahu’s doctor tried to kill him even though he is an expert physician because he was not just a non-Jew, he was a heretic (he may have been a Christian). The enmity of this group against the Jews is sufficient that they would be willing to die in order to cause them harm, just as Samson was willing to kill himself in order to kill the Philistines.