What the Miami Heat have accomplished in the fourth quarter of their past two games has been particularly notable, with a season-high 37 fourth-quarter points in Friday night’s victory over the Orlando Magic and three nights earlier outscoring the Boston Celtics 23-13 in the fourth quarter of that win. What has been missing has been particularly noticeable, as well, with point guard Kyle Lowry appearing in neither of those final periods in the two home wins. Coach Erik Spoelstra said the decisions had nothing to do with the recent knee soreness that had limited the 36-year-old veteran. “The last game,” Spoelstra said of the victory over the Celtics, “the second unit really took over, and they deserved to play that out.