@Booster
Yes! It teaches you: you shouldn't try to save everyone! Let them help themselves! And they will reward you!
I do find it very odd myself... I still think either A)
If a tree falls in the forest and nobody is around to see it... did it really fall?
or B)
Perhaps that point where the division of two universes collide, and if you jump down there; you're no longer in Kansas anymore.
or C)
Booster fixes the teleporter with his last breath, and it sends him to Sand Zone, where a dog with a Life Pot in its mouth awaits.
or D)
Booster conveniently appears in the teleporter all of a sudden unharmed. Teleporters are known for their reality bending properties. Booster probably just used the buffer memory of the teleporter, to put humpty dumpty back together again.
or E)
Booster v0.8 dies. I'll be back. Now, Booster v2.0 lives.
or Z)
Pixel was trixy
EDIT:
or G)
Booster is haunting the island as some kind of corporeal ghost. It's why he doesn't go back home.
Afterall if Pooh Black in the labyrinth can haunt the clinic, perhaps Booster can come back too. Only strange part is the teleporter. But, perhaps although Quote sees him clearly, maybe looking at him in the mirror would reveal a floating pair of Glasses.