After learning the סוגיא of בא במחתרת I was filled with a bunch of questions regarding what is a בא במחתרת.
The Gemara סנהדרין דף עב ע״ב seems to answer my question by telling us that the reason anyone is allowed to kill for בא במחתרת is because he (the בא במחתרת) is a רודף.
If that's true,
1) What is the reason for the differences between a רודף and a בא במחתרת?
If you see a רודף, you are obligated to kill him/her, whereas if you see a בא במחתרת it would seem according to Rashi you have the option to kill him/her if you desire but you have no obligation to.
2) Why does Rambam place a בא במחתרת in the גניבה section in his משנה תורה? Whereas רודף is in רוצח.
3) There are commentaries that say (cannot recall who right now) that there's a difference between a רודף and a בא במחתרת since they have different intentions (one's to kill, one's to steal) therefore a בא במחתרת is one that isn't out to kill you per say but if he sees you, he will. He will not seek you out though. Whereas a רודף is looking and perusing you to kill you.
4) A רודף we kill because of what he's doing right now, where a בא במחתרת is killed for his further sins.
5) If you can save the נרדף in any way other than killing the רודף, you must (according to most). Is that the same in a case of בא במחתרת? One commentator states that it wouldn't apply in this case because it's dark and therefore since the בא במחתרת is just popping out of the tunnel, the homeowner doesn't have time to think if there's a way to save his life without killing the הא במחתרת and therefore he's allowed to just kill him.
6) Finally, why does the Gemara use the rule:
הבא להורגך השכם להורגו
Why wouldn't it say the reason you may kill the בא במחתרת is because he is a רודף?
So with all these questions, although the Gemara says the reason anyone is allowed to kill his is because he a רודף, is he really a רודף? Maybe not a full רודף?
How could one answer all these questions and make this idea of a בא במחתרת make sense?