Deep shallows
So Ashildr shows what it might be like to be stuck for eternity as a confused teenager. Perhaps now she's got an irritating older man around he'll act as sand-paper to smooth off some of the raw edges.
Interesting reference to Captain Jack. Hint of more to come from that angle?
I'd be intererested to know where the doddery old 17th century butler got to know about cocktails. I think there could be more to this episode than meets the eye.