Corrected entry: On the roof, after Det Harrigan climbs the ladder, he checks his gun. The sound of spent cartridges clattering can be heard. Subtitles reflect this too. The Desert Eagle is not a revolver, and only ejects cartridges when fired. If he was reloading, it would be with a magazine.
lionhead
18th Jun 2023
Correction: He is not reloading it; he hadn't fired it since the start of the movie. He probably checked it and a bullet or cartridge got stuck in the barrel. He gets rid of it; you hear it falling, and then he repositions the slide. You hear only one cartridge fall.
lionhead