As a 7th dan in Aikido maybe Seagal is a badass, but, I am sorry Conner, Seagal was never a Navy SEAL, in fact he was never in the military. He played an ex-SEAL in the Under Seige movies... I have read several times where Seagal makes vieled claims that he killed for the CIA on top secret missions and such but have no reason to believe they are anything other than b.s.
Marcinco must have been joking around or something... and don't forget that except for Marcinco's first book and his business book, everything else he ever wrote was fiction.
p.s. It looks like he does mention Seagal once in his novel Red Cell when he says, "On my way north on Avenue of the Stars half a dozen chattering teenage girls, with $100 dollar jeans with holes in the knees, po' boy sweaters and imitation boondockers asked if I was Steven Seagal. No, I said, smiling, I really DO kill people for a living."