You can listen to the air traffic control recording of this "incident" on LiveATC.net. It sounds like a perfectly routine go-around and certainly nothing approaching a "near miss."
The communication is a little tough to make out, but apparently there is some sort of vehicle that was crossing the active runway. After the controller asks US67 to go around, he explains, "I apologize, the machine says to go around, even though the vehicle is clear, so we have to send you around anyway." The pilot responds, "I gotcha." He sounds more inconvenienced than at all alarmed.
Again, not sure exactly what the deal was the vehicle on the runway, but this definitely doesn't sound like anything but routine.
To listen to the recording for yourself, go to LiveATC.net and click on Live Feed Archives on the left-side menu bar. Download the BOS Tower recording (mp3) for April 20 at 1900Z. US67 first checks-in at the 17:30 mark, and the go-around is around 18:50.