ulp.... if these are the mirrors I am thinking of I may have done the same thing when tired. Put my foot on the bottom part to stretch the leg a teeny bit. The mirrors were always sturdy and I never thought of them falling.
I'm gonna have to check tri fold mirrors next time I'm in a store...
I suspect the hinges weren't properly attached. I can't imagine how a 3 year old could have gotten it off the hinge?!
It is SO tragic ... poor baby...