go off

verb

1. To explode.“The bomb went off right after the president left his office.”
2. To fire, especially accidentally.“The gun went off during their struggle.”
3. To explode metaphorically; to become very angry.“It all went off when the opposing teams' fans met at the railway station.”
4. To begin clanging or making noise.“Just after he spotted the first plane on the horizon, sirens started to go off around the city.”