On a trivial note: Spock's sideburns here are a huge improvement over the way they looked at the end of "Such Sweet Sorrow". I think the Spock shouting bit is just an in-joke. And, like I said before, I'm really glad we're getting to see Number One again. She drew the short straw during S2. One other thing: this is a bit of a parallel. We saw the beginning of Burnham's assignment on the Shenzhou in "Battle at the Binary Stars" and now we're seeing the beginning of Spock's assignment on the Enterprise.