the camera has the whole group in the shot... if you watch Lukes mouth you can make out "what was that"...
i think we discussed this earlier on the board....
some thought he was saying it to himself...
but i have a feeling if he was saying it to himself he wouldnt make it so obvious...
and then theres the whole Luke calling Leia "Carrie" when he gets back to Yavin after destroying the death star....