[Tom Tetroxide]

Depending on how heavily loaded a 737 is, a climb rate of 3,000 to 4,000 fpm isn’t uncommon.

With all that kinetic energy after a drop like that, as long as the aircraft doesn’t exceed the posted Vne in clean configuration, hitting an 8,500fpm climb rate is within reason.

[rdcbn1]

Well, it's not so much the 8500 fpm climb in and of itself, it's the transition from the 10,000+ fpm dive from 16,000 ft to a pull out a 400ft agl followed by an immediate 8500 fpm climb that I find a rather impressive maneuver.