The only thing about time re-setting itself is that people would need to either handwave a whole week or simultaneously play out the loop and real time - either of which could get confusing.
Unless averting the catastrophe meant that time leapt ahead to catch up with the outside world.
ETA: And in re-reading what you wrote, you didn't actually say time would re-set, you said it would return to normal... so that could mean catching up with real time?
Re: More specific!
The only thing about time re-setting itself is that people would need to either handwave a whole week or simultaneously play out the loop and real time - either of which could get confusing.
Unless averting the catastrophe meant that time leapt ahead to catch up with the outside world.
ETA: And in re-reading what you wrote, you didn't actually say time would re-set, you said it would return to normal... so that could mean catching up with real time?