Good explaination, one technical pointer or useless information, however you wish to interpret it!
A loud bang is heard on a compressor stall due to the formentioned 'stage' 'stalling'; airflow has disrupted and has ceased to move over the area due to a number of variables. The high pressure air compressed beyond the area of disruption moves back into the low pressure region causing the surge and a large bang.
The combustion area can become very hot at this stage as the airflow through it has stopped. If the temperature has exceeded engine limits the engine cannot be re-started, but more than often and in this case the aircrew were able to see it was within limitations, cool the engine down by allowing it to windmill and commence a re-start.
