突破口
太平门

Sally \Sal"ly\, n.; pl. {Sallies}. [F. saillie, fr. saillir. See
Sally, v.]
1. A leaping forth; a darting; a spring.

2. A rushing or bursting forth; a quick issue; a sudden
eruption; specifically, an issuing of troops from a place
besieged to attack the besiegers; a sortie.

Sallies were made by the Spaniards, but they were
beaten in with loss. --Bacon.

3. An excursion from the usual track; range; digression;
deviation.

Every one shall know a country better that makes
often sallies into it, and traverses it up and down,
than he that . . . goes still round in the same
track. --Locke.

4. A flight of fancy, liveliness, wit, or the like; a
flashing forth of a quick and active mind.

The unaffected mirth with which she enjoyed his
sallies. --Sir W.
Scott.

5. Transgression of the limits of soberness or steadiness;
act of levity; wild gayety; frolic; escapade.

The excursion was esteemed but a sally of youth.
--Sir H.
Wotton.

{Sally port}.
(a) (Fort.) A postern gate, or a passage underground, from
the inner to the outer works, to afford free egress
for troops in a sortie.
(b) (Naval) A large port on each quarter of a fireship,
for the escape of the men into boats when the train is
fired; a large port in an old-fashioned three-decker
or a large modern ironclad.