People inside a shop at night while other people walk around outside.
People are indoors while other people are outdoors.
People indoors are shopping at night while the people outdoors are walking around.
(x)
exists p1 p2 x1.(exists p3 x3.(exists x4.((x3 = x4) & n_outdoors(x4)) & -(x3 = x1) & n_people(x3)) & n_people(x1) & n_people(x1) & while(p1,p2) & exists x2.((x1 = x2) & n_indoor(x2)))