Headscratchers / Star Wars: The Rise of Kylo Ren

• Why Luke didn't think on destroying Ren's helmet at the Jedi outpost on Elphrona once the Knights of Ren left the scene? If he had done so, then Ben could have been left with no means to contact Ren years later after destroying Luke's temple and he could have never fall to the dark side nor joining the Knights! And even if Ben didn't fall to the dark side, another individual could have come to Elphrona, find the helmet and join the Knights...
  • Maybe Luke didn't suspect on the possibility of Ben falling to the dark side nor that he would ever return to Elphrona, though it's a bit unclear why Luke didn't speculate on the possibility after what happened to Anakin. He also possibly thought that the probabilities that someone would find Ren's helmet and its uses were slim.
  • It's also implied that Luke had to use the Force offpanel to open the Jedi outpost's entrance, as he noted that the entrance was sealed. He possibly thought that if any other individual ever found the outpost, he/she would be unable to open it either for not being Force-sensitive or because they would not understand the outpost's significance. Thus, if no one knew how to enter, there was no reason to destroy Ren's helmet, as it would be sealed inside. Then again, Luke likely dismissed the possibility that someone with Force training like Ben would enter the outpost once more.
• So, in The Last Jedi, Luke says that Ben left with a group of students after killing the rest, but the only students that leave besides him do so in order to stop him, not to join him. Was Luke just mistaken about the events and assumed that Ben hadn't acted alone, or is this just another continuity error for the comic?
  • I think it's just an error, but perhaps Luke genuinely believed this to be true when Tai, Voe and Hennix didn't return to the temple. Since Tai was Ben's closest friend Luke might have believed Ben corrupted Tai, while Voe's rivalry with Ben and Hennix's interest in the Force could have caused them to follow Ben for different reasons. It's a weak explanation but it's the only one I can think of.