The aforementioned mission about Kerrigan storming a lab simply requires you to attack move forward as the game floods the halls with Zerg units you fling at the poor Terrans.

FORBES: Starcraft 2: Heart of the Swarm Review - Part 2

On behalf of my fellow Terrans, thank you.

WSJ: 2013 Lexus ES 300h Review: A Smooth, Elegant Guilt-Eraser | Rumble Seat by Dan Neil