It's not too much of a stretch to think that rebels can infiltrate the flagship. There are thousands of sailors, Marines, and Spartans aboard, so at least a few of them have serious ties or even just little bits of sympathy for colonials dreaming of independence. CAPT Lasky was fond of the will and determination of the Insurrectionist cause and CDR Palmer herself had parents who held contempt for Earth's rule.

Anyone wishing to board Infinity only needs to look at the fine print. A ship with a full complement of 17,000 crew requires immense logistics to keep her, the ship's company, and the Marines healthy. All they need to do is smuggle themselves aboard in-uniform and head for the armories. From there they'll have free reign to create havoc.

It's ridiculous to think that the Marines and Spartans would let this happen aboard the flagship, but spirited and motivated individuals will undertake the impossible. I wish them the best of luck!