Time Jump Theory
It's probably just a whimsical fantasy-SciFi thing in the minds the writers, and it works on that level. But it may actually make a little sense theoretically:
-To time-travel, you would need to disconnect from the cause-and -effect stream of the Universe.
-Then you need to move somehow.
-You would be in a kind of quantum mechanics free-fall, not attached to any time period, but going forward or backward.
-Quantum physics has something to do with lasers--the time jump device had a laser.
So maybe there's some SciFi plausibility to it, at least in a token sense.
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The story is king.