Kdot wrote:They know the location of the bridge and are headed directly in that direction
Consider the defensive technique used by our neighbours to the south of the border. The Whitehouse is not easily hidden. Would-be invaders might seek to destroy it in an effort to snip off the governing head of the country. Unfortunately for them, during a national emergency, they will never catch both the captain and the first officer in it at the same time. If anything, attacking the Whitehouse during an invasion is playing into the hands of hte defenders.
Capturing the ship is the main goal, which requires taking the bridge and engineering. If you can capture the senior officers, that's icing on the cake. No self-respecting captain would allow themselves to be captured (think Admiral Windsor, who blew up her ship once they captured her). Consider Captain Rabidius, who surrendered, bringing shame to the Praetorian Fleet.
Next pass, I can add more tech to slow them down. The defenders can't use gas because the attacking force is wearing head-to-toe bodysuits, including rebreathers. Artificial gravity is treated as if it can't be controlled in limited areas of the ship. Even that were possible, the lack of gravity can be overcome with special boots that cling to whatever the ship's decks are made (e.g., magentic boots).
Also, don't forget battle chess. There are rules that only allow certain configurations of ships: some combination of command ships, dreadnoughts, and cruisers, with maximum crew complements per ship, including the number of marines/classiarii onboard each. The Imperium has more ships overall than the Realm, which is a violation of the treaty. The Imperium is bankrupting itself doing so.