Suicide of all kind is haram (regardless of whoever commits suicide and for whatever the reason), be that suicide is for honour, to run away from worldly miseries, or to kill enemies in battle. In war, even if there is possibility that suicide could turn a battle, then also suicide is haram. All who do suicide for whatever reasons die a death of kufr and are Jahanummi. Apart of that Allah has forbidden suicide, reasons are obvious too, and those reasons are:
Those who are Muslim and believe on Allah, believes that this life is test and everything whatever happens in this world, Allah is always in control. Thus for Muslims, victory, defeat, gain, loss, occupation, independence, honour, pain, wealth, misery, blessing, good or bad future, everything is in the hands of Allah. Allah test individuals and occasionally whole community collectively, through all these things. So, a Muslim tries to change things according to his abilities and rightful means, but at the same time tries to accept all situations without getting depress, desperate, or running away from test (committing suicide). Anyone who does not believe that Allah is in control of everything and does not accept that situations and circumstances are part of test, than that person is not Muslim (in belief), and if anyone dies with this belief then the person dies a death of kufr (death with disbelief on Allah).
Those who rely on suicide for whatever reasons do not believe that Allah is always in control of everything, and thus they want to change things with their suicide (so that they can avoid something in life or change something around them). These people kill themselves intentionally. If they had believe on Allah, they would never run away from his test by committing suicide for whatever reasons (as their belief that all is in the hand of Allah, and this life is test, would stop them committing suicide). Anyone who dies with belief that everything is not in the hand of Allah, thus they can change thing with suicide, and that this life is not test, that person dies a death of kufr (disbelief) and would end up in Jahannum. Unfortunately, those who really commit suicide for whatever reasons, at time of suicide they die with belief of kufr (disbelief) and since they are already dead with no chance of repenting, they (like all who do suicide) become jahannumi.
[Note: Anyhow, if a person really find himself in such awkward situation that the person has to jump into danger and death is imminent then also that person should think that he could save his life from that situation and he should really try to save his life even if chances are almost 0 percent to survive, as that is necessary if that person do not want to die a death of kufr (that means, even if that person dies, his intention should be not to die). For instance, considering 1965 war ... if some people took bombs and hid somewhere in front of Indian advancing tanks with intention to put the bombs in front of the tank and escape, knowing that there was almost 0 chance of escaping, and hence in the process they died, than that is not suicide even though some might say that it was suicide, as their intention was not to die.]