Final answer:
In 'Illuminae,' the Phobos virus was unleashed in Bay 4, causing major repercussions for the characters and the plot.
Step-by-step explanation:
In the book Illuminae, the Phobos virus was released in Bay 4. This event is a pivotal moment in the storyline, resulting in catastrophic effects on the people aboard the spaceship.
The release of the virus plays a significant role in the plot of the Illuminae series as it causes widespread panic and sets off a chain of events that the protagonists must navigate through. For more information read the context.