The narrator explains that truthfully, the robber released the Realtor and the seven prospective buyers all at the same time. The eight hostages walked downstairs and got into police cars, while the policeman waited in the stairwell for his colleague. The special negotiator called the robber’s phone, but moments later the police stormed the apartment and found it empty. Either one of the hostages helped the robber escape, or the robber is still in the apartment.
The novel introduces more intrigue here as the narrator suggests that the hostages may have helped the robber escape—does this explain the Realtor’s absurd babbling? Or, as the police seem to fear, is the robber still hiding in the apartment? This remains a mystery for now, but it’s worth noting that the narrator (and perhaps the police) seems to be jumping to conclusions about what might have happened.