Saniflo over flows when electricity cut out

Hi
The other day, there was an electricity cut out in the area and we were using the shower and toilet. There is a Saniflo installed here. The break in power seems to have caused a overflow and a leak (causing alot of damage to downstairs ceiling). Since the electricity came back on, the Saniflo is working alright and there has been no further leaks. Why was there an overflow from the Saniflo in the first place? surely the system should have been designed to prevent this. And the other concern is - could it happen again (even if there is no electricity cut off)?

Any help would be useful thanks.

A Saniflo is an electrically powered pump, if there's no power it wont work. It doesnt have storage capacity in event of power failure, simply if the electricity goes off again, dont use anything connected to the Saniflo!

Thanks Hugh. Understood.
The only problems is that when you are in the middle of a shower or on the toilet when there is a power cut, then there is going to be flow of water anyway......

I know that cannot be avoided, but in that event should the power go off, stop showering! W.C. pan should hold the contents of one flush until such a time as power is restored and Saniflo can restart to pump it away.