I'd pull out "old reliable" a 16 oz titanium framed single shot
firing a .50BMG loaded with 220 grain palladium plated
pre-fragmented hollow magnesium bullet packed with
phosphorus traveling at 3800 ft/s from a 5" barrel. Nice thing
is that the BG will probably burn up without leaving more than
a greasy stain on the concrete.
If you time it correctly, you can use the recoil to split the skull
of the bad guy behind you too!