I've read that this click is due to the ear's reaction to the strong
electromagnetic pulse. If that's what you heard, it comes from the ear
itself, not from outside................................

According to old Gary Coffman posts, he says it's picked up by the
auditory nerve. Also, deaf people can hear that click.
I've had two strikes to my mast with me sitting 15 ft away from the
base of the mast. I could hear that click, but I also could hear
the arc sound of the strike going to ground outside. Sounded
like a light bulb being thrown to the ground outside my window.
Not that loud really. I'm fairly convinced the quality of the ground
connection effects the loudness of the strike. The strikes that hit
my well grounded mast are fairly quiet, not counting the overhead
sonic boom. The strikes to the trees in the yard are super loud
in comparison. A loud crack, instead of the quieter arc sound.
MK