Kanan, too, lets his eyes drift closed. He doesn't try to match his breathing to Hera's, because that's more distracting than anything else -- possibly especially to her, but --

He does focus on it to the exclusion of the gears, the sound of the mechanical parts of the prowler slowly fading away from his conscious mind, replaced by breath through the lungs and faintly, just on the edge of perception, the pounding of blood through veins and vesicles and arteries.

His own does not keep pace with it, but for a fleeting moment, maybe he wishes it would. But he keeps breathing, and Hera keeps breathing, and eventually he forgets to pay attention and drifts off into his own deepening sleep.

It's a pleasant one.