This verse is points us to the spaces or voids between the breaths, and to our ability to be both attentive to the breath and pauses, and at the same time remain aware of the external world in a multi-sensory, panoramic way. Swami Lakshmanjoo, a key teacher of this lineage invited students to focus on those spaces with attention "unbroken, continuously refreshed".
For the next few weeks, I invite you to get familiar with, fall into, rest in, and explore the spaces at the ends of your breath...
From Lorin Roche:
Radiant One, the life essence carries on its play
through the pulsing rhythm of outward and inward movement
This is the ceaseless throb, the rhythm of life...
The inhalation, the return movement of the breath sustains life
The outgoing breath purifies life
These are the two poles between which respiration goes on unceasingly
Between them is every delight you could desire
Even when the senses are turned outward, your attention on the external world,
Attend also to the inner throb, the pulsing of the creative impulse within you