All four of the Arrowverse series have been stellar this season, but Supergirl and Legends have been the most "focused" thus far in terms of laying out their overall narratives, and are the series I would rank at the top right now.
For me, this was the first week that the Earth-1 shows impressed me this season. All three of them were kind of iffy before, but they all pulled it together and pulled off excellent episodes this week. I hope they can keep it up.
(Victor Garber belting out Edelweiss to a room full of Nazis was utterly hilarious brilliance)
I didn't put it together until now that "Edelweiss" is from The Sound of Music and that that's a movie about escaping from the Nazis. Is there some more specific significance to that song in the musical? I haven't seen it in ages. (I'm not really a fan of "Edelweiss," because back in high school I had a watch whose alarm played "Edelweiss" in rather strident, shrill electronic tones that always jarred me even after having years to get used to them. I got deathly sick of that melody. Fortunately, it's been long enough that that visceral reaction to the tune has faded.)
I loved it that Stein did a Marty McFly homage. "Key of A, watch me for the changes, and try to keep up." Not verbatim, but close enough. I wonder if there was a guy on the phone offstage going, "Richard, it's your cousin Marvin Rodgers! You have to hear this!"