i would think that the air in that room would get stale really fast man. You are not going to be able to seal that room 100%, differences in indoor/outdoor temperature are going to cause +/- pressure.
so for working at "night time" during the flowering cycle, ive seen green lights reccommended. However, if you are growing a strain that has a really dark/purple (IE Blackwater) hue to it, wouldnt a purple or "blacklight" bulb be the way to go?