Attacked suddenly (7)
(Other definitions for pounced that I've seen before include "Suddenly sprang" , "Swooped in attack" , "Was jumping" , "Moved fast" , "Sprang (like a cat)" .)
(Other definitions for ambushed that I've seen before include "Taken by surprise in war" , "surprised?)" , "Attacked (someone) from concealment" , "Lay in wait and waylaid" , "taken, surprisingly" .)