I worked for an FCCS/E8 on my first ship. He’d gotten broken up somehow and couldn’t continue being a SEAL. He was small guy, probably 5’6” and 150 pounds. Would do the PRT push-ups on one arm. Never learned any specifics of what or where he did his time while with them. He was a seriously squared away and professional guy. Later I learned he’d got commissioned. I don’t if it was in the regular navy or as a limited duty officer.