You fell victim to one of the classic blunders: conflating velocity with its derivative.
The (approximately) zero-G period lasts for minutes, not milliseconds, and during that time, the velocity changes by 9.8 m/s (22 MPH) every second. The velocity should not pause at 0, or any other value.
22 mph per second is an abomination of a mixed unit I'd never heard before, but it's actually much more intuitive to me than the standard 9.8 metres per second per second.
Maybe we can compromise on 35 km/h per second though.
New Shepard is not traveling perfectly vertical, there's always a horizontal component so the velocity will never be zero. Even if you fly up in a perfectly vertical line, you'll gain horizontal velocity as you climb as the Earth's surface moves away from you from it's rotation.
It’s possible it experiences zero-G for more than just a few milliseconds at its apogee. Hence the 0mph velocity.