An ambush is a surprise attack. Concretely, it may represent some unpleasant surprise or unanticipated turn for the worse in one’s life. If one was headed for a clear destination at the time of the ambush, it may represent a sense of being blocked. Ambushes may also be more general symbols of sudden loss and emotional upheaval.
the positioning of an army unit or of partisans, prepared well in advance and thoroughly camouflaged, on the most probable route of advance of an enemy with a view to defeating the enemy with a sudden strike, capturing prisoners, and destroying combat equipment. The Russian word for ambush, zasada, denoted the garrison in the cities of the Russian state of the 16th and 17th centuries. The zasada was headed by a voevoda (military commander or governor).