Or just your episodic memory taking over for a brief period, this is why so many minor car accidents happen close to home. Your brain says "We've done this so many times before I'm gonna stop observing this familiar environment and let your memory fill in the gaps." If you are severely sleep deprived you may also be experiencing moments of micro-sleep. Your brain literally falls asleep for short periods of time and you have no memory of it happening.
I just get into the zone and I realized I leveled 20 times and got 30 pieces of gear