For anyone who understands how odds work, Las Vegas currently has Dallas -280 to win their series against the Lakers while Miami is -650 to beat the Celtics and move on.
Just by going off of these odds, Las Vegas is saying that the Lakers are more than 2 times as likely to comeback and win their series as the Celtics are.
I realize the Lakers and C's are playing different levels of opponents, but those numbers also take into consideration that the Lakers lost two home games and would play 3 of the next 4 on the road while the Celtics lost their games on the road.