(Eftachbchinor: I have been keeping to the mandate you gave me, but I think the mandate itself would mandate that I respond here.)
1) There are several stories in the Talmud about the Angel of Death being unable to kill someone because he was engaged in Torah study. (E.g. King David in Shabbos 30b, Rav Chisda in Makkos 10a, Rabbah Bar Nachmeini in Bava Metziah 86a.)
2) Rabbeinu Bechayei in Kad Hakemach “Torah(A)” discusses this idea and then raises the question:
??? ???? ???? ????? ??? ?????? ??????? ???? ??? ????? ??? ???? ??????? ??????? ????
and answers:
??? ??? ?? ????? ??? ????? ??? ?????? ??? ??? ???? ??? ?????
3) As to other mitzvos, this is discussed in Kiddushin 39b. The Gemara records that R’ Yaakov and (according to one version) Acher saw someone ???? ?? ???? ??? ????? ???? ?? ?????? ???? ????? ???? ?? ??? ???? ?? ????? ???????? ??? ??? i.e. he was simultaneously fulfilling ????? ?? and ????? ??? and he died. R’ Yaakov used this as the impetus for his shita of ??? ???? ???? ???? ????. However, it seems from the Gemara that even within ??? ???? ???? ???? ???? there is a concept of ????? ???? ??? ?????? and therefore the Gemara attempts to explain how the person could have died. The Gemara’s conclusion is that it was ???? ?????? and ?? ???? ????? ?????? ?? ?????? ?????. There are other potential ways to answer as well, involving different aveiros, but as people have pointed out, we don’t want to speculate about this.
Also, the Maharsha on this Gemara references the Mishnah in Avos (4:19) which says ??? ?????? ?? ????? ?????? ??? ?? ?????? ??????? which many commentaries explain as referring to the fact that we can’t understand H’s calculations about why bad things happen to good people and vice versa. (See http://www.theyeshivaworld.com/coffeeroom/topic/the-world-to-come-and-gilgulim#post-531184 and the continuation there.)