Just to clarify... (or possibly confuse further)
Lawr / i lawr (one l) means down.
Llawr (two ll) means floor.
Therefore, i lawr ar y llawr would mean down on the floor.
Llawer means many or several.
There are many people down on the floor would translate as - Mae llawer o bobl i lawr ar y llawr.
What you probably heard in this case is lawr, lawr, indicating that they needed to go down to the next floor/down the next flight of stairs. Had his daughter seen low flying ducks coming towards her father, she may well have shouted llawr, llawr indicating that they should drop to the floor.
Or of course ot could well have been this...
This is true!!!