Bomb in Callahan's car
How did they plant the bomb into Callahan's car without being noticed ?? It was parked outside of a restaurant !
shareRemember the car in the parking garage?
That bad guy took about 3 seconds to unlock it.
Another bad guy (there were at least two on scene) could also have been a lookout and shielded him from view during those 3 seconds. Once inside the car - no one would have paid any attention to somebody fiddling around inside the car.
In a party town area like that people are busy having fun and not paying attention to their surroundings (even though that city may have a reputation for crime).