Thread title is wrong. OKC has the tiebreaker so Dallas isn't 0.5 games out of the play-in. They would need to win their last two games AND have OKC lose in order to make the play-in, and Memphis has nothing to play for so it's pretty much guaranteed that OKC was gonna win their final game if they wanted to.
If Dallas was actually trying to miss the playoffs, they wouldn't have played Kyrie 43 minutes and Luka 38 minutes in a 123-119 win over the Kings in their previous game. But then the Thunder beat the Jazz the next night, and it looks like they saw the writing on the wall at that point.
Dallas was shot, they didn't really have a chance anymore.