saved by the bell
rescued from a bad situation at the last minute (as in the bell at the end of each round in a boxing match), to be rescued from a difficult situation just in time by something that brings the situation to a sudden end

[TahlilGaran] Dictionary of Contemporary English ▲

Saved by the bell.
something that you say when a difficult situation is ended suddenly before you have to do or say something that you do not want to.
Luckily, my bus arrived before I had time to reply. Saved by the bell.

[TahlilGaran] English Idioms Dictionary ▲

saved by the bell
rescued from a bad situation at the last minute (as in the bell at the end of each round in a boxing match); to be rescued from a difficult situation just in time by something that brings the situation to a sudden end
We were saved by the bell when the meeting ended before we had to deliver our badly prepared presentation.

I was saved by the bell and do not have to give my presentation until tomorrow.

[TahlilGaran] English Idioms Dictionary ▲