go down

(intransitive) To fall (down), fall to the floor.

Example:   You'll need to go down two floors to get to that office.
2010, Stefan Molyneux, Heroism :
  You can be heroic and start the process of truly saving the world before the Sun goes down tonight.
  The unemployment rate has gone down significantly in recent months.
  The boxer went down in the second round, after a blow to the chin.