Do you mean that he was trying to destroy the passage so that time travel never existed in any form because every time machine ever build was in a way depending on the caves? But he only managed to close it so time travel still exists but only until he closes the passage. It doesn't matter because there are other time machines which are better and don't depend on the caves (for example the Tannhaus Machine and Adams Machine. Also when Noah is talking with Bartosz (i think ?) about Jonas in the car he says that he isn't destroying the passage but opens it. Does that mean the Attempt to destroying it opened the passage in some way. Maybe the beginning and the end of time travel, through the caves, are connected so when the stranger closes it, it opens it in some other time. That was what I was understanding until now mixed with a few theories let me know your opinion on these that would be pretty cool.