If the sofa was against the wall there would not be room for Madeleine to fall and lay long enough for blood to seep through the tile.

If the sofa was away from the wall, wide enough for her body to lay, I would have thought there was enough room for her to walk behind the sofa.

However, looking at the photos, I can see  there was a table at one end and a wall at the other.

The tiles have only been lifted on one side of that area...just behind one side of the sofa and the small table.