The later and bigger, I think that fits more of a choke job.
I mean halftime anything can happen. in regards to the Final FOur game or the Bills Oilers game. If one team can get out to that big a lead in one half, the other team can do the same in another half.
The other thing is when there is a lot of time on the clock and one team has a huge lead it's natural and unintentional for refs to be more merciful on the losing team. That's over all sports. The team losing might get a really tick tack mercy call while the team with the big lead wont get the same call. That often can be a catalyst or a least play a small part in a big comeback, at least initially.