Team America to the rescue!
Just kidding, we know the US portion of the Internet eats that jingoistic crap up, but Bullshido isn't in the clickbait business.
Anyway, US Airman Spencer Stone is a blue belt that trains with Team Gracie Lisbon, where he is stationed. He and two other servicemen were on a train in France when they became aware of a man with an AK-47. Without fanfare, they sprang into action.