We've witnessed two swirling votices (i.e. portals) thus far.  The one Cole experienced was black and he saw the "dirty, bearded men" on stairs.  Presumably this was a 'bad' vortex.  The one Andy entered was white and transported him to the Fireman's lair.  Presumably this was a 'good' vortex.  Hulk Hand saw the Fireman, so I assume it was a white vortex.

I think this ties in with the whole black/white (i.e. evil/good) theme.  It also applies to what was behind Laura's face (white) and Sarah's (black).

Any thoughts?

(I've searched to see if this has been discussed, and haven't read every topic, so apologies if this is a rehash.)