Monster color DUH question

[jrichview]

I must be dense. To me the monster color roll is unclear.

When I first read this monster rule:

5. Newly explored rooms always have a monster! Draw the top
Monster card and find the monster’s standie. Roll the Monster Die to see
what color its base is (the player of that color gets a DxM). If no bases of
the rolled color are available, you get to choose the base – but the player
of the chosen color does not get a DxM! If no bases at all are available

... I assumed the colored die only had 4 possible colors. Had I considered that assumption for an extra 10 seconds or just examined the die I would have realized quickly that you can't fairly represent 4 colors on a 6 sider.

We have only played this game once, but we figured we should just reroll util we got one of the 4 colors. Is that what everyone does? If not, what happens when one of the other two colors comes up for monster color?

Seems like it could be stated more clearly one way or the other.