How'd he do that? #1

[Mike McCarty]

I thought it might be instructive to examine this remarkable photograph. This photograph of the "Beatles pillow fight" was taken by the legendary Harry Benson in 1964 at the hotel King George V in Paris.

Aside from these obvious and remarkable circumstances, I'm struck by the technical difficulty that this scene presents. There is a great deal of of movement which seems to have been sufficiently stopped. It shows an adequate depth of field, which the position of the subjects would require, and yet there doesn't seem to be a frontal flash.

There could, however, have been a good window / balcony door light source coming from behind and to the right of the camera, but still this seems remarkable to me that the motion was stopped.

Maybe you could answer the question:

How'd he do that?