ㄌㄧˇㄧㄥˋㄨㄞˋㄏㄜˊlǐyìng‑wàihé

里应外合
  1. 裡外相應外邊進攻裡邊響應裡邊起事外邊接應 細作混入夜半四處點火裡應外合」。

to coordinate outside and inside offensives (idiom)​, (fig.)​ to act together