There is a simple explanation for your experience. The energetic alignments within your gung fu movement, in combination with your focus, opened some internal energy channels. Being fully 'present' was key in your experience of this 'flow' as you refer to it. If you would have shifted your focus to 'think' about the experience, it would most likely have stopped, pretaining to your heightened sense of your surroundings and awareness. There is a spiritual energy piece "possibly" connected to heightened experience, spiritual energy/qi, spiritual channels too, just like internal physical channels , that can open, but,,,,,
just from a phyical/universal energy channels opening perspective, what you describe is possible. Being fully present in the moment, free of thought , or free of thought other than a given focus, in and of itself, can produce the heightened sense of surroundings as you describe.
Intuitive sense stems from the upper dan tien. Although focus in martial expression is lower dan tien focus,
you do have a middle and upper that "are". Everyone's level of development regarding, say, the upper dan tien is different.
Some people come in with their third eye more open than others. You are interconnected regarding these three dan tiens.
Again, some channels opened for you. A good teacher would simply say that, and tell you to go back to what you were doing,,,,,your focus. Leave ego out of it, and the mind out of it.