Driven into hiding by state-of-the-art policing technologies, Anderton must leave The Sprawl when technology seeks him out. A patrol moves from building to building in search of their fugitive dropping “spiders” to scout out and scan residents. These self-guided, metallic gizmos scurry into homes for mandatory retinal identification; however Anderton’s eyes need more time to heal from his surgery. Opening them now could leave him blind, and so he submerges himself in ice water to block the spiders’ infra-red sight.