It's science fiction adventuring and action at its best.
During your adventuring, you always seem to encounter a barrier door that is missing a lever to open it.
You can also find bonus clips hidden in treasure chests while adventuring.
It had always been assumed during previous discussions on the question that warships adventuring the passage would try a rush, that they would endeavour to steam by the, batteries and drive the `defending gunners from their guns by concentrated fire.
Weapons and armor can be purchased at a limited number of shops or found during adventuring.