The large and heavy quadruple crossbow
mounted here is manned by one gnoll (hp 6), who can easily watch the 10' wide
north-south corridor through a peep hole.
Any intruder in the passage is subject to
four shots at once, each inflicting 1-8 points
of damage. Make "to hit" rolls with a + 5
bonus, i. e. 9 or better to hit AC 2 when fired <THACO 11>
by the gnoll sentry. As the crossbow cannot
be reloaded and wound in less than two full
rounds, it is unlikely that it can fire twice in
a melee. (Use your judgment as to the sentry's actions, which should definitely
include warning its companions. )

The crossbow is not easily moved (encumbrance 400 gp) but can be dismantled for travel. It can be sold for a base value of 50 gp.