In Force Awakens, Han says to Rey:

This hyperdrive blows there's gonna be pieces of us in three different systems.

Wookiepedia states:

the Millennium Falcon possessed a Class 0.5 hyperdrive, while top-of-the-line battlecruisers such as the Imperial I-class Star Destroyer contained Class 2 hyperdrives.

If the Millennium Falcon can separate like this with only one hyperdrive, it is probable that a matrix or individual hyperdrive failure would cause separation of the Death Star. This failure would be very rare, given all the security measures hyperdrives employ. The engineers of the Death Star presumably put in defense measures against this too.

Although it should be noted that the quote you provided mentioned 123 hyperspace generators rather than hyperdrives. I don't know if there's a difference or if that difference is significant.

In Force Awakens, Han says to Rey:

This hyperdrive blows there's gonna be pieces of us in three different systems.

Wookieepedia states:

the Millennium Falcon possessed a Class 0.5 hyperdrive, while top-of-the-line battlecruisers such as the Imperial I-class Star Destroyer contained Class 2 hyperdrives.

If the Millennium Falcon can separate like this with only one hyperdrive, it is probable that a matrix or individual hyperdrive failure would cause separation of the Death Star. This failure would be very rare, given all the security measures hyperdrives employ. The engineers of the Death Star presumably put in defense measures against this too.

Although it should be noted that the quote you provided mentioned 123 hyperspace generators rather than hyperdrives. I don't know if there's a difference or if that difference is significant.