Heart of the Swarm Campaign- Dominion Space: Conviction (Part 3)

The next room to the Northeast contains four locations where virophages can be planted, releasing constant streams of infested Terrans that will automatically attack towards your goal location, tying up the main bulk of the Dominion forces.  The Northeast end of the room is also occupied by another Terran fortification, which includes three Goliaths you can try to swipe if you like, though they may well be destroyed either by the surrounding Dominion units or your own assault forces before things can work out right.

The next room is only lightly defended, and will also grant you a drop-in of some more zerglings and a third queen for your use.  Once the room is cleared out and Sarah moves in, the far door will open and a small platoon of ten or twelve reapers will dash in, easy fodder for a Fungal Infestation or Sarah's Crushing Grip.  With the reapers destroyed, the infested Terrans from the virophages will continue to the Northeast through the gate, pursuing your primary goal.

Here you'll need to cross a non-retractable bridge towards the last Dominion holdout here- a batch of emplacements and troops set up by the coupling to the prison deck.  As Sarah advances, the Dominion commander orders the coupling destroyed, to sever the prison decks from the rest of the ship.  You'll need to take out the enemy forces quickly enough to stop them from breaking the coupling, which takes the form of a structure built into the Northeast wall.

Once the enemy forces are torn down, Sarah will board the elevator in the midst of the final room to head down to where Jim is- as Arcturus starts the ship's self-destruct to destroy Jim alongside all of the unwitting Dominion prison guard.  Your other troops will thankfully make the trip as well, leaving you in the Northeast corner of a new map.