I won't even pretend like I understand the circumstances in this shooting, but one officer fired 31 times (according to the Yahoo!NEWS article). I don't have a working knowledge of fire-arms, but I believe that a standard magazine loaded hand gun holds 17 bullets (including the one in the chamber). That means that officer Oliver had to reload his weapon.
Doesn't that give you a minute to think, "Is that guy really armed? Should I really re-load and fire 14 more bullets into this vehicle?"