Some time ago I read a short story that started with "time police" arriving to arrest the protagonist, who grabs one of the police's devices and hits the button. This triggers a series of time jumps as they chase him, and he finds that he has already prepared for this.
One part I recall was that he time-jumps into a rubber dingy with several cans of shark repellant. When sharks appear he panics and uses several cans, but then realizes they work for some time so he can pour them out one at a time. It turns out he has exactly enough cans to last until he drifts to land, even accounting for the ones he dumped out in panic.
I seem to recall this was in a collection, not a magazine, but it might have been a book-like magazine like Analog. I read it in the 80s, but it was definitely an older story, although with the shark repellant it couldn't have been from before the mid-60's?