Apparently the defensive switch at the end was the suggestion of Covington:
In an unusual move before Brooklyn’s final possession with 14.5 seconds remaining, Saunders made three substitutions. He took out Jeff Teague, Towns and Wiggins and replaced them with Okogie, Jake Layman and Noah Vonleh. That came at the urging of Robert Covington, who said he suggested to Saunders to get member of the Wolves’ second unit on the floor, a group that helped the Wolves build an 18-point lead in the first half.
“Just by putting our bigger defensive lineup in, ultimately we wanted guys who could switch at all times,” Covington said. “No harm to anybody else, but it was just the guys who played really hard on defense. All can do so many different things, and that's what we needed, especially in that moment.”
Saunders took out Towns because he had five fouls and wanted to prevent him from picking up foul number six in case Brooklyn decided to attack the rim and go for a quick layup. That way he’d at least have Towns for the final offensive possession.
The intangible benefit of Covington. Glad to have him back.