In some martial arts some moves block/punch at the same time.  In running you simultaneously breathe/move your legs.  In other sports/endeavors, there is similar overlap.

We all love the Zen cliche, “Do one thing at a time,” but it is entirely possible to focus 100% of attention on breathing.  So where does that leave us? To only act between breaths?  When I look deeper, the message reveals itself:

Not to hem/haw over engaging in one action per moment, but to engage in a purity of focus that renders all actions singularly sublime.