Sitting a powder keg is an idiomatic expression that refers to a dangerous situation where conflict or disaster may occur at any moment. In order to avoid using the same phrase repeatedly, there are several synonyms that can be used as alternatives. "Playing with fire" implies foolishly engaging in risky behavior without considering the potential consequences. "Walking on thin ice" suggests that the individual or situation is fragile and could easily break under pressure. "Ticking time bomb" emphasizes the imminent danger and the idea that something explosive could happen at any moment. "Highly flammable" invokes the image of a combustible substance that is ready to ignite.