It's possible the guy was actually a decent shot, and didn't intend to hit anyone. Were the two hits direct, or ricochets?
If he was trying "suicide by cop" why didn't the cops oblige him? Did he run out of ammo? Bad ammo management? Very slow cops?
If "assault" is the charge, I'd guess it's because the DA can't charge him with more.
I'd bet he comes up with a "mental" defense.