What Epsilon actually describes is more of a meditative visualization than a lucid dream.

A lucid dream is when you are fully asleep and become fully aware during a dream. Something in the dream triggers you to recognize that something isnt "quite right", and then you realize that you arent actually wake, but are dreaming.

It occurs during REM stage sleep. Lucid dreaming has spikes of upper-alpha and beta brain wave activity during REM, which is why you become more aware in the dream.

But it doesnt last long, because the brain eventually phases out of the regular REM stages and you wake up.

But if you have regular lucid dreams you can prolong them each time it occurs. #1 - Dont be scared during it. The most common reason people wake up immediately during it is because they get scared that they wont be able to wake up and be stuck in a dream state. Or fear they will create conditions in the dream that will be terrifying.