a world of heads that connect to nothing
just heads that seem to float across each window unconnected to anything. As in disconnected floating heads.
Context
Kate's depression has dissolved the street into free-floating heads attached to nobody, other people reduced to disconnected imagery in dark glass, and the scene turns that perceptual collapse into a plot mechanism: because she registers the human world only as detached heads, the one head that matters — her stalker, matching her step for step — slides in unseen. The failure to perceive others as continuous people is exactly the gap the predator walks through.