I had already posted my assumption here:
Since Elli has already announced that she has something else to do that evening, the question of the return journey will be clarified in advance of the concert. Sam, with shining eyes, suggests bringing Sophia back in his car. Sophia accepts the offer and Elli and Patricia leave the concert early. Of course Sam will definitely want to show Sophia his secret place with a view of the sea on the way back. This place will be well hidden and wildly romantic. Sophia we say something like "I can't believe that there is such a magical place near the city. As if from another world ...". That is then Sam's cue for further progress.
That this place is not on another world proves Liam's call, who asks where his wife is and tells her about Cathy's invitation.