Today, Trevor McWilliams works for the defense company Lockheed Martin as an engineer. While it’s impressive, it’s nothing out of the ordinary, right? Lockheed is a big company that employs hundreds if not thousands of engineers.

That’s what you’d think before you watched this video and allowed McWilliams – a former sergeant in the U.S. Army Airborne Division – tell a story that is both inspiring and incredible. In keeping a promise to himself, McWilliams is helping to produce cutting-edge military technology – and saving tomorrow soldiers’ lives in the process.