Is it likely that water can enter below the slab?
There's typically a drainage system around the inside perimeter of the basement (perimeter drain), which feeds into the sump pit.  If the pump is not removing water, the drains will fill just the same as the pit. 

Water always finds level, so if it's above the rim of the pit, it's also filled the drains.  So theoretically, water could seep in anywhere around the perimeter of the basement.  

Once it's found a way in, it could fill the basement like a pool.