I dont think he has visited william before, if he did that already, william had already been dead, as I dont think he can protect william once leaving before battle tower, since a horde of black ring will auto attack once trying to go down the stairs after the conversation with william.
I was able to. Yeah, that's cost a lot to escape these 2x leveled punks, but I did. And, when I leveled up, I have returned and kicked their asses.