This is the normal saucer separation mode of the Exodus class. The Aviary, Photon and Bat class ships remained docked together in one unit, and the Mjolnir class forms another unit.
This is comparatively a time consuming process, because normally the Photon class is physically coupled to the Mjolnir class and only connected by passageways to the Aviary class. During this process, physical couplings are engaged to the Aviary - which is slow - and disengaged from the Mjolnir - which is fast.
This is not recommended in emergency circumstances.