In Mystery Spot, Dean's deal didn't come due till about halfway through the six months he was dead.
The Trickster is Gabriel is Loki.
Hel Lokisdottir.
Dean never went to hell in Mystery Spot, no matter what Gabriel said or Sam thought. Dean went to Hel. And even when Dean's deal came due, since she had him already, maybe she could keep him. Neither Hel nor Gabriel could rescue Dean from hell—Hel might have been entirely unable, Gabriel couldn't without breaking cover, which probably would have ended about as pleasantly between S3 and S4 as it did in S5—but if Dean went to hell in Mystery Spot then Gabriel would have had to, wouldn't he? But not if Dean went to Hel instead.
The Trickster is Gabriel is Loki.
Hel Lokisdottir.
Dean never went to hell in Mystery Spot, no matter what Gabriel said or Sam thought. Dean went to Hel. And even when Dean's deal came due, since she had him already, maybe she could keep him. Neither Hel nor Gabriel could rescue Dean from hell—Hel might have been entirely unable, Gabriel couldn't without breaking cover, which probably would have ended about as pleasantly between S3 and S4 as it did in S5—but if Dean went to hell in Mystery Spot then Gabriel would have had to, wouldn't he? But not if Dean went to Hel instead.