They still dart back and forth implying activity dreams- happens during our/your sleep.
At about after 90 minute mark, you would of fallen into a deeper, slow sleep. You then switch into a cycle sleep as known as rapid eye movement, a.k.a REM.
Rapid eye movement is when the
most graphic like and frequent dreams happen.
Signals in your brain are controlled by certain neurotransmitters which
wakes us up from a bad dream. If we didn't have that, all we'll be doing is screaming unaware. However your eyes remain responsive to these signals.