

It’s not a plot hole because:
spoiler
The show explains that during the moment of the apocalypse, time stands still for a short while. This is what Martha uses to keep the time loop going, but Claudia uses it to continuously gain more information about the loop they are in (by giving accumulated knowledge to her younger version). Then, using this knowledge, she makes Jonas & Martha use this same moment to travel to the origin world.
If that’s a plot hole, so is the whole time loop.
No problem! I didn’t really understand it during my first watch either, but rewatching a bunch of times definitely helped. Hope you enjoy!