The dreamscape that the four of them 'awoke' into was a sandy beach, bathed in the light of sunset. Similar, though not exactly like the beach of Destiny Islands.
The reason for this was that it was not Margaret's dream which had taken shape, but Song's. When she became aware of this, she let the vision fade into formless dream-stuff, balancing the control of it between the four of them.

Then she went about locating the others. Hopefully they could find each other and prepare themselves before Maleficent acted up. If she did.
.... Oh, who was she kidding? Of course Maleficent was the one causing trouble. If the phylactery was any indication, it had to be.