Was the tower ever under threat ? :spoilers:

[Colton Grech Micallef]

Hi everybody I'm new here so I may be a little inexperienced. I have had this question since I read the books,

?

For the tower ( or gan ) to send Roland back repeatedly for him to reach it makes me wonder whether it was ever under real threat from the destruction of the beams. If Roland's journey had already happened the first time through - Which the last book suggests that it had been done many times repeatably - Is it knowingly putting itself at risk again by risking the destruction of the beams ? Or all of this was prevented the first time Roland journeyed to the dark tower and all consecutive Journeys were all just repetitions or perhaps figments of roland's imagination ?.

I hope this is understandable and please bear with me as this is my first attempt and english is not my first language