Updated

A young paramedic in South Dakota was surprised enough to see a police car pulling her over -- but even more surprised when the officer got down on one knee.

Rapid City Police posted the dashcam video to Facebook, under the title, "In pursuit of the perfect proposal."

At first, 22-year-old Sarah Stewart didn't seem to know what was going on. Senior Officer Dan Anderson walked up to her minivan and asked her to step outside.

But as she walked toward the patrol car, her eyes lit up. Her then-boyfriend, 23-year-old Officer Nick Allender, approached her and took the ring box from Anderson.

She said yes. They shared a hug.

Allender told ABC News he wanted the moment to be "unique, and something that I could do that was different than anyone else."

His fiancée, who works for the Rapid City Fire Dept., said she was in "total shock."