From what little I've read, I understand a typical 737 stall speed to be in the region of 110kt with everything hanging out, more like 130-140kt clean.
No idea what winds aloft were like, but surface winds at the time were in the order of 6-8kt.
This crate lost 170kt in about half a minute, if the data's to be believed, ultimately reaching a
groundspeed of 115kt. That has to be getting close to the stall, if not actually beyond it. Could that sharp right turn be explained by a spin entry?
At 07:36 you see the rate of climb fall off while the speed decreases, although this is groundspeed not airspeed so harder to draw conclusions. That said: Are we seeing pilot/autopilot hauling back on the stick to arrest a sudden sink due to windshear? Did they then drive it straight into an even meaner cell that did them in?
Let him that hath understanding count the number of the beast:
For it is the number of a man; and its number is One hundred threescore and twelve.