At the bank…
I think there’s way too much crowd noise at the bank. You just don’t have that many people in a bank at any given time.
And again, be careful with that reverb. Think of the physicals space of a bank. Even if its a large bank, with stone or cement floors, most are not going to have 50ft high ceilings.
I would also consider fading the police sirens in as they get closer to the scene. Those sirens are also of a cop car in motion. Its almost as if you’re running along side of a cop car…not stationary with the police car approaching from the distance. Once the police pull up on the scene, you need a short siren blast, because once police are on a hostage scene, they leave their flasher on, but turn the siren itself off.
Here’s one more thing to think about…if you had a psychopath committing an armed bank robbery with an automatic weapon, you would a mob of cops descending on that bank like a bunch of drummers at NAMM. So as the firing continues, I would add more layers of police sirens in the back, as multiple squad cars would surely be racing to the scene. Just make sure you use slightly different sirens that are offset by panning position and pitch.
…another note, use ambulance sirens too. They would undoubtedly be called to a mass murder scene like this.