If he survives ( a life-threatening situation he put himself in) with the help of the Creator, may he be exalted; he will lose his merit and reward, as our Masters of blessed memory have said of this " A person should never stay in a dangerous place and say that a miracle will be performed for him lest no miracle be performed and if it is perfomred for him his merits are diminished ( Shabbos 32a)

 When Shmuel Hanavi set out to anoint Dovid Hamelech, he took precautions to protect his life from Shaul Hamelech, who would have indeed taken revenge if he knew Shmuel was on his way to anoint another King.  We see from here that even though Shmuel acted on H'shem's command, one must always take precautions to protect the life and body H'shem gave him.  pg 405

One who exposes himself to leather danger commits suicide resulting in leaving GD's service. This is considered rebelling against Him and deserves severe punishment pg 403

 GD has cautioned us not to kill any human being in any way, saying, " Do not murder" (Shemos 20:13). The closer his relationship to the murdered person, the more culpable the murderer is.   Accordingly, as none is closer to a person than he is to himself, he who kills himself undoubtedly deserves severe punishment. For he may be compared to a servant whose master ordered him to guard a certain place for a certain amount of time, warning him not to abandon his post until the arrival of his messenger.  When the servant saw that the messenger was late in coming, he abandoned his post before the latter came. pg 403