Hum. Do you mean all the doors that leads to other places? Hum. I've never thought about that. Well, that's just one little thing, the main plot in Monsters Inc. is that the cute little kid becomes friends with the monsters and I think that it's to explain to kids that monsters aren't dangerous. :)
And the main plot in Matrix is that the world is not what it seems to be, that what we believe is The World, is acctually a giant computer program called The Matrix and then there are some people trying to free us from that illusion.
But yes, the doors are very similar. Hum. Well, it's a great idea and it's been used before as well, just not in the same extension. A lot of horrormovies uses doors that leads to other worlds, and the same is for when illustrating dreams. :)
"Always forgive your enemies; nothing annoys them so much."