His Big Ten title time was .61 seconds faster than the next time of 46.63 produced by Champ Page of Ohio State, and is also the fastest collegiate time in the country this indoor season.
Here is an excerpt from an SK.com story with the qualification for the NCAA indoor championship.
"Brown captured the Big Ten indoor title in the 400m with a time of 45.62, currently the
third-fastest collegiate time in the country and the fastest by a freshman this season. Brown’s mark is also a school record, which he previously set on Jan. 9 during the Rutgers Invitational with a time of 46.61."
I think Brown's time may have been the fastest at the time he ran it but it may have been surpassed later in the day from another meet.
Either way, it is a fabulous time and is a threat to win an NCAA title.