"Systems generally need to fail safe in the open position with local means of disconnecting the power supply to the lock so that escape can be assured even if other circuitry fails to release the door." It's about the design of electrical locking systems.
As said by Hot Licks, the meaning lies in the word 'fail safe'.
It means: A device which in the event of a specific type of failure, responds in a way that will cause no harm, or at least a minimum of harm, to other devices or to personnel.
Hence, these kind of electrical locking systems need to be fail safe to ensure no harm is done even in the case of a power or even a circuitry failure.