come to a boil
1. Lit. [for a liquid] to reach the boiling point. The soup came to a boil and the chef reduced the flame.
2. Fig. [for a problem or situation] to reach a critical or crucial stage. (Alludes to water reaching an active boil.) Finally, things really came to a boil. Everything came to a boil after Mary announced her engagement.
3. Fig. [for someone] to get very angry. Fred was coming to a boil and clearly he was going to lose his temper.