Ah, now I see it...
Originally Posted by Gabriel
About 14 seconds later (and 33 seconds after the initial notification that the runway was closed), the controller instructed the flight crew of Delta flight 1999 (the next arriving airplane for runway 13) to go around.
The danger wasn't coming from Delta 1086 at that point, as it was well off the runway, but from the snow coordinators vehicle's presence on the runway (as he had already reported to ATC twice that the runway was closed).
However, this assumption led to a situation in which the snow coordinator’s vehicle was on the runway for about 23 seconds while Delta flight 1999 was on final approach. At the time of the controller’s go-around instruction, the flight 1999 airplane was only about 30 seconds from landing.