Mitzvah #237. And it seems to me that if one ends their own life with full knowledge and awareness of what they are doing, and someone else can save them, it's possible that they are not obligated in the prohibition of "don't stand idly by the blood of your neighbor" and for the positive commandment of "and you shall reserve [their property] to them" which comes to include returning one's "self" (lit. body) to them, for the obligation of returning a lost object does not apply in a case where someone loses their money intentionally / with negligence, as it's explained in Shulchan Arukh Choshen Mishpat 261. This prohibition is not cautioned against, as the Talmud challenges in Sanhedrin 73a: Why do we learn to rescue someone who is drowning in a river from "do not stand idly by?" Rather, we learn it from "you shall return it to him." This suggests that "you shall return it to him" includes returning one's body/life to them. One cansay the practical difference between these is with a case of someone who ends their life with full intention and awareness, that one is not obligated to "return their life to them," as they are not obligated to return their money to them. If so, you must say that the Torah wrote this prohibition of "don't stand idly by the blood of your neighbor," even though this too one is not obligated [in this case]. So it seems clear to me.