12 Million Hostages full explanation

12 Million Hostages Conan, with his friends and with police officer Sato, visits a cafe and is told that the cafe they were heading to was investigated by the police as there was a bomb threat and all the customers had to be evacuated. The two police who searched the cafe, Shiratori and Takagi said there were no bombs found, Takagi stays while Shiratori says he will go somewhere and enter the car, but he immediately opens the door, only for the car to explode. Shiratori said he is fine but Conan observes paralysis in one half of his body and bleeding from his head and assumes its acute epidural hematoma, and immediately calls an ambulance. Conan deduces this case to be specifically targeting police officers. Conan reasons that the bomb was set when the two police officers were investigating the cafe as that is when they will leave the car empty and it's the only time that it's possible as a bomb set in the car before would likely be discovered. Conan assumes the criminal did this in secrecy by hiding in the crowd as a large crowd will form once the cafe’s customers are emptied out. Conan further infers that the trick likely involved the safety pin of the bomb releasing once the door of the car is opened and ignited once the door is opened once more, which explains why Shiratori was able to get in the car by opening the door but the car exploded right after. From this line of reasoning Conan knows that 1. Its targeting police officers as the main bluff of the cafe bomb was a …