You can't really see what happens, but you know it's heroic.
That's State Trooper Eric Devers, who leaps over a guardrail to save a truck driver that had crashed off the highway in Miami County, Ohio. According to the video's description:
An officer with the Ohio State Highway Patrol was honored this week for saving a semi-truck driver's life back in April. Dashcam footage just released shows trooper Eric Devers arrive at the scene of a crash and immediately sprint toward the driver. The trooper found the man still belted into his seat. Shortly after, his eyes rolled back into his head and he stopped breathing, the Ohio State Highway Patrol said.
The truck driver apparently had an atrial fibrillation, which is a quivering or irregular heartbeat that caused him to pass out while driving.
And hey! How cool is CPR? You should learn it yourself and become a hero like that guy there.