I think Spo made a mistake putting Bam on Tatum last night. Boston's counter was to accept the matchup and simply let the rest of the offense play 4-on-4 with Miami's only paint protector stuck to Tatum on the perimeter, and that enabled everybody else to do whatever they wanted. Brown ruined Herro in the paint, White stayed hot, and the rout was on from there.
I get the thought - put your best defender on Tatum - but I generally think putting a big on-ball against Tatum is a bad move, particularly in Miami's situation where they don't have any other playoff-caliber interior defenders. It doesn't typically bother Tatum much to begin with (see: G7 against Philly last season), and it also unlocks a lot of other weapons for this offense.