Gordon knew this damned robber was implying that the hostages he had released might be carrying bombs. The seasoned detective knew it was a common tactic among robbers.
Many professional robbers did not take everyone in a bank hostage at once. Too many people were difficult to manage and required more manpower to watch over. The scenes shown in movies and TV dramas, with dozens of people tied up and sitting on the floor, were unrealistic.
In reality, the number of hostages was generally around five to twelve. The exact number depended on the size of the bank, the local police force, and, most importantly, the strength of the local media. In places with more aggressive media, they could take fewer hostages. The media would turn it into "five families' tragedy" anyway and pressure the police.
With pressure on them, the police would cooperate more readily. As long as the hostages were rescued in the end, their work passed the line; whether the money was recovered could be dealt with later. That increased the robbers' odds of escaping.
There was also a knack to releasing the excess hostages they did not need. Those hostages could usually tie up the police for a while, so the robbers generally released them one at a time at intervals.
First, the police needed to learn about the situation inside the bank from the released hostage, and questioning was unavoidable, which diverted their attention. Second, they did not completely trust the released hostage and had to check them for dangerous items.
Some particularly cruel robbers turned such people into human bombs. If one exploded in a crowd, it would inevitably cause enormous chaos and distract the police even further.
Even the mere possibility that the person walking out might have a bomb on them could