So to get to alpha max, one has to apply sustained full back stick. I'm guessing that this means that as the full back stick is applied, the alpha limitter progressively increases its limit value from alpha prot to alpha max.
Out of curiosity, how much delay would this entail?
Also, I recall something about Airbus fbw going to "direct law" at expected landing radar altitudes, and that this mode gives the pilot direct stick-to-pitch control. Could that have been the pilot's motivation for going so low? To have a better feel over the remaining pitch authority?