I don't see Abell indicating much different.
In formal portraiture it's not any different. If shooting for a smile, one shoots for a fresh smile rather than one that is waning... If you are shooting Churchill you get ready then steal his cigar and shoot.
To me machine gunning is simply shooting things indiscriminately. "Oh, something's going to happen. Hold the trigger down until it's over."
For HCB catching the subject at the perfect moment, in the perfect composition, and in focus (DOF) was everything. Grain, perfect exposure, and how hard the minions in the lab had to work were of no concern to him.