"Polundra!' (sometimes also palundra and falundra) is an exclamatory interjection that arose in the days of sailing fleets and originally had the meaning "watch out from above!" It was used in those circumstances when the sailors working on the masts dropped anything from their inventory or tools from a great height onto the deck. The "Polundra" is a battle cry unique to Russian navy/naval infantry and used since at least the 19th Century. During the Great Patriotic War (World War II), the word "Polundra!" served as the battle cry of Soviet marines. Currently, it is most often used as a synonym for the word "beware!" Thanks to Egor Yevsikov for the research and translation.
In fact, while celebrating the relief of the Legations with the 5th E. Siberian Rifles, the sailors were not informed of the imminent departure of the Sissoi Veliky and were left behind. Unknowingly, they were off the muster rolls of the battleship but fortunately their commanding officer, Kapitan-leytenant (Lieutenant Commander) Yury Andreyev sought out Polkovnik (Colonel) Nikolai Aleksandrovich Tretyakov, commanding the 5th E. Siberian Rifles for help.