Typically this style is achieved when each film frame is captured at a rate much faster than it will be played back. When replayed at normal speed, time appears to be moving more slowly.
I was trying to get my wife to the hospital before she gave birth to our first child but a group of slo-mos caused her to have the baby in the back seat of my new Mercedes.
Someone that just doesn't quite get it.
I just cussed you out, told you to get out, and you're still here...you a slo mo.