What does this dream mean?? Red door, grey corridor.?

Basically i've had this dream so many times and I never understood it. But the setting is a grey corridor like space with one red door and lots of grey doors. If you went through a grey door you go to another universe which is bad and each one is different, like lava, just white light, falling through the sky for ever. But the red door was the right one and I never went through it, and when I did I woke up. What does it mean??