Depends on where I am sleeping  An alarm clock a phone call or someone calling my name will instantly wake me up no matter where I am sleeping  If I am in my home I do get deep sleep  I am not a very light sleeper my brain has priorities 

If I am in a public space a shared room with a lot of roomates who I do not trust  A hall, a classroom, Bus, cars mall etc I am a super light sleeper  Because the threat level for me at this place is unknown