Thud!

Thud went the carpet.  In every home with a baby, everyone instinctively knows what that sound means. 

Sammy lay flat on his back after falling off the sofa.  A second later he started bawling.  And then Pia started sobbing. 

She had been taking care of Sammy.  Sammy sits between her and the sofa's backrest. That way, Pia keeps Sammy away from the edge of the sofa. But when she stood up for a moment to get something from her desk, Sammy fell.

It must have been some fall.  He has scratches and a mild bump on his forehead from the fall.