Antonio said:
ok, but now what does it mean "Not on my watch"
This can be used with any form of guarding or caregiving.
A security guard of a shopping center must watch for intruders at night. His friend says, "There have been a lot of break-ins here lately." The guard says to his friend,"Not on
my watch!" meaning, he is a tough guy, a good security guard and he is not going to let anything happen.
Another example:
A teacher is on yard duty, which means to watch the children play at recess. A child comes up and says, "Tom and Bobby are running through the water!" The teacher says, "Not on my watch," and goes over to stop the boys from running through water.
Not on my watch is a way to say ,
I won't let anything bad happen while I'm watching or guarding.