Have you ever had a dream where you are free-falling, only to wake up in bed? Ryan Campbell, wasn’t dreaming when he fell down a 60-foot cliff in the Daniel Boone National Forest in Kentucky, but he was sleeping. He is OK, suffering only minor injuries.
While fully awake people can fall, the likelihood is increased when sleepwalking while camping near a cliff. –Jim L. Wilson
Being alert is more than merely being awake, it is watchful diligence.
1 Peter 5:8 (HCSB) Be serious! Be alert! Your adversary the Devil is prowling around like a roaring lion, looking for anyone he can devour.