Then they go silent as Hiro abruptly disappears. He has switched over to his small, invisible avatar. He is hovering in the air now above the shattered remains of the egg; gravity takes him right down into the center of it. As he falls, he is muttering to himself: "SnowScan." It's the piece of software he wrote while he was killing time on the liferaft. The one that searches for Snow Crash.