The cat may have been injured or sick. Cats have a peculiar tendency to hide when they're in pain... it's the same brain mechanism that makes them run from a threat. Of course, they can't escape internal pain, so they just stay hidden.

I've had to rescue many a sick cat from under beds and other hidey-holes, often at the expense of some arm skin, when not even tuna and catnip would get them to come out.