Going to sleep and dreaming within the dream (levelling as I like to call it) is typically a delving deeper into the subconscious fears and desires. I like to think of it like levels of a labyrinth...though sometimes it may seem like circles in hell, depending on what you fall into.

Lucid levelling is not terribly uncommon (in the lucid world, anyways; lucidity in general is uncommon). People get roused about levelling moreso from it happening naturally. Most natural levelling only moves one level, MAYBE two. (I flipped out the one and only time I naturally levelled two levels deeper.)