In the nick of time
Definition 1 of 1
Pro Tip 1/3Time Sensitivity
Describes a critical moment where any delay would result in failure or a missed opportunity. 
She submitted her application just in the nick of time.
Pro Tip 2/3Urgency
It carries a sense of urgency and implies that the action was done hurriedly to avoid some kind of negative outcome. 
I reached the gate in the nick of time before it closed.
Pro Tip 3/3Dramatic Effect
Often used to add drama or excitement to a story, highlighting a crucial moment. 
The hero arrived in the nick of time to save the day.