Linus Visits David in Bed, Explained：see her for the tree

- Good. ... and sat down like a jerk.

The punchline to Linus's account of the tennis-court disaster: David stood up like a man for Sabrina, then "sat down like a jerk" — which is how he ended up on the broken glasses.

- How do you feel? - I never felt better in my life.

David reports on his recovery with his usual swagger: not merely better, but the best he's ever felt. The line is cheerfully oblivious, given the stitches.

I was blind, that's why. It's been Sabrina and I since we were kids.

The confession: David says he was blind to what was in front of him, and that he and Sabrina go back to childhood — suddenly she is the obvious answer.

I know how these things bore you, but would you mind keeping an eye on Sabrina for me?

The request that gives the scene its title. David frames it as a nuisance for Linus, then asks him to watch over Sabrina — the favour Linus will turn against him.

I don't want to go to Butte, Montana. You're going to help me, aren't you?

David's real fear is exile to the family's Montana copper mine. He needs Linus's help, and asks in a way that assumes agreement.

And no more false moves now, not until those stitches are out.

Linus's closing instruction: David must stay still and make no mistakes until the stitches come out — a medical warning that doubles as a way to keep him out of the way.