Hi. Im new to this site and the whole concept of lucid dreams , recall etc.

This may seem like a silly question but anyway - If ure sleeping and suddenly woken up either by someone or if you have to go do ure thing sometime in the nite does the dream cycle restart ? or say if u were in an REM phase would you pop back into it?

Also is the 4th stage the deepest state of sleep?

Sorry for the many questions but i am kinda confused