The scene switches to evening, where Doc in the town square setting up the equipment necessary to send the DeLorean Back To The… time frame that Marty is used to. And Gipe, again taking every opportunity to drop in a brand name, explicitly tells us what kind of car Doc drove to the town square - it’s a Packard! Be sure to remember this information because it will never ever come up again!
Next to it is the DeLorean, covered in another tarpaulin. Doc whistles and looks over his work: “a very expensive 500 feet of triple-strength wire from the lightning rod atop the courthouse to the connection he had just made” and hah hah I guess that big speech Doc made earlier about killing the future President of the United States by buying something that wouldn’t otherwise be bought is out the window!
Doc turns to Marty and tells him he’s going to miss him when he’s gone:
"I… well… I’m gonna be sad to see you go. You’ve really made a difference in my life. You’ve given me something to shoot for. Just knowing that I’m going to live to see 1985… that I’ll succeed in this… that I’ll get a chance to travel through time… well, it’s gonna be hard for me to wait thirty years before we can talk about everything that happened in the past few days. I’m gonna really miss you…"
And hah hah I guess that big bit where Doc shouldn’t know too much about his own future is out the window too! But I’m glad the “it’ll be hard not to talk about this for 30 years” line from the movie is there, because it blew my mind as a kid to imagine Doc meeting Marty for the first time after this, having to act like they’re strangers, but knowing what great friends they’ll become. YAY PALS! PALS FOREVER!!