A very long shot, IMHO.
MARDET is smaller than you think, and with some topside covering fire, they will have to wait to engage the enemy.
As for the size of the ship...that does not directly impact getting access to the magazine. Up the forward brow, forward along the deck, enter the ship, down a few decks...
A very long shot, IMHO.
About as long a shot as flying some airliners into the WTC and the Pentagon.