Recruit: Aye, aye, sir! Aye, aye, sir! Aye, aye, sir! Aye, aye, sir! Narrator: This is Marine Corps boot camp in Parris Island, South Carolina. Before they become United States Marines ...

The biggest difference between his Army ROTC training and Marine boot camp was that Brooklier was ... like squared-away uniforms, according to Brooklier. As a budding Army officer, he had been ...

Narrator: This Marine Corps recruit isn't actually injured ... Narrator: It's part of their final test at boot camp, known as the Crucible, a 54-hour event that all recruits must complete.