Same HS, Same nuke sub

While standing an "under instruction" (apprentice) watch as Officer of the Deck of a USN nuclear submarine in the Pacific Ocean, my over instruct and I talked about why we seemed familiar to each other. Short version: We were one year apart from the same high school out of New Mexico, a state that has about 1.5 million people in it and had been on the varsity track team together although we had competed in different areas (he was a distance runner, I was a shot/discus thrower). Additionally, his younger sister married my best friend's supervisor several years later. I'd known her for about four years without knowing that connection, and it came up when she mentioned that her brother was moving to my area for six months of training and needed a room to rent, reconnecting me again to this odd coincidence.