The action is the juice.
The cops really made awful decisions in trying to catch them in the act in a place with a million bystanders. They already suspect them of being behind the triple murder and robbery in the beginning.
The first 2 cops ‘hide’ behind the U-Haul truck, where some guy is sitting in the driver’s seat, minding his own business. Chris easily sees the cops and fires and most likely wastes the poor guy, as you see the front windows get all shot up.
Mann's realism is mostly unmatched and they were trying to take them in the act, as a last resort, they really didn't have much evidence of any crimes committed. the risk level to the public was extremely high, to catch bank robbers, but they were using fully automatic weapons and takeover style robberies. Something similar happens in
Point Break
but yeah, this isn't exactly normal police procedure- lol- There's a scene in
Miami Vice (2006) when they move to takedown the drug trafficking network, by essentially running a sting operation, where the
police will be executing the gunmen using snipers, which is uhh questionable legally