Currents and buoyvance
For those still doubting what a 5-6 knot current can do, it's all in the buoyancy of the fin. The impact with the surface of the sea was obviously sufficient to buckle the aft pressure bulkhead, tear off the apu and elevators and dislodge the heavy recorders but leave the fin intact enough to float, gradually sinking as water filtered into its and the rudder's compartments and finally coming to rest when its anchor, the remains of the aft fuselage, snag on the ocean floor.
Did you read about the divers working downwards hand over hand on the buoy cables and being streamed out like flying Supermen? Imagine a semi-floating object, sinking only gradually. I'm surprised the tail was found only 1.7km from the impact point.
Regarding recorders being found "under the wing", at that depth, in murky water, wing or elevator would look the same. I'd assume elevator.
Finally, many divers are by nature consummate risk-takers. I'm not one but have butted heads with a few. it looks as though they've been lucky so far but I hope to hell they're careful over the coming days. Grim work.