Imagine how Luke and Han feel right now. It’s funny how this scene should actually have a lot of tension. But as a viewer, we know that Leia is okay due to the fact that she raised her head to see the scout trooper explode into flames before she slipped into oblivion.
Lucas could have made us nervous, though. He could have introduced an entire subplot of “What happened to Leia?” Instead, he quickly showed us Leia is fine in the scene immediately following this, and the other 2/3 of our heroes find her quick enough.
With this scene however, I like to believe that Luke could sense that she was still alive and hopefully, could sense she was okay. From just reading this scene in the script, I can’t tell who is more worried. It actually seems like Luke is more concerned that she hasn’t returned. But knowing this in context and understanding our characters as we do, I believe Han is more worried than Luke. Just because, again, I would like to think Luke senses she’s okay through the Force.
I do appreciate the lines given to Threepio at the end of the scene. He always has these great lines in the OT that are really lacking in the Prequels.
Do you remember his lines in AOTC? It was basically slapstick comedy (“Oh, this is such a drag!”). Not the worst thing in the world, but not the Threepio we know from the OT. The Threepio in the OT had a personality, whereas the Threepio in the Prequels did not have as much screen time and when he did, did not provide the comic relief like we were used to. I hope Abrams sees that small detail and writes some lines that make Threepio a gloomy, grumpy, anxious, chances-of-surviving golden protocol droid again.
EXTERIOR: SCOUT CAMPSITE – FOREST
Han, Chewie, and the droids, along with the rest of the squad, wait anxiously in the clearing. Artoo’s radar screen sticks out of his domed head and revolves, scanning the forest. He beeps.
THREEPIO: Oh, General Solo, somebody’s coming. Oh!
Han, Chewie, and the rest of the squad raise their weapons.
Luke steps out of the foliage to find the weapons trained on him. He’s too tired to care. He plops himself down on a boulder and looks around.
HAN: Luke! Where’s Leia?
LUKE: (concerned) What? She didn’t come back?
HAN: I thought she was with you.
LUKE: We got separated.
Luke and Han exchange a silent, grim look. Luke gets up wearily.
LUKE: Hey, we better go look for her.
Han nods, and signals to a Rebel officer.
HAN: Take the squad ahead. We’ll meet at the shield generator at 0300.
LUKE: Come on, Artoo. We’ll need your scanners.
Luke, Chewie, Han, and the droids move off in one direction as the squad proceeds in another.
THREEPIO: Don’t worry, Master Luke. We know what to do.
They move off into the woods.
THREEPIO: (to Artoo) And you said it was pretty here. Ugh!
Star Wars Anonymous 
Those Threepio lines in AOTC make me want to cry whenever I watch it…so bad…
You and me both, sister. I wouldn’t mind so much if they had set up Threepio to have those kind of punny lines from the get go and that was his character. But since we knew Threepio differently, it was painful to hear that stuff even uttered