I remember the days of Johnny Walker and the "Chairman of the Boards" and those two athletes seemed to break the world indoor mile record at will. Judging the way Ingebrigtsen looked he could do the same as it looked like he had a lot in the tank.
PS this record was held by a fairly obscure Ethiopian before this run. Hicham's outdoor world record is 3:26 and that hasn't been approached in years.