In
The Words of Hurin and Morgoth Morgoth says about his family "They dwell now in my realm, and are at my mercy," to which Hurin replies "You have none". How does this reflect (or not) what actually happened?
I think we would all agree that Turin's fate (let's just call it that for now and not get into that beaten debate) was anything but merciful. But considering his suicide - is that the least merciful way to end his life and suffering? Could it not have been worse?
I guess Turin was at such a point then that Morgoth could do nothing else to make him suffer further.
Also, Turin overcame himself in the end - and overcame all which his fate hung by. Even though he was mad when he committed suicide, there is still an element of sanity to it (unlike Nienor, who jumped of pure horror, grief, and feeling of helplessness/despair about the powers that toy with her family). He understood that his death is better than his life - not only for himself, but for everyone else too. Is that not what he was greatly urged to do all his life - understand his
inability, forget his pride? And when he finally did it he found peace, though by far not the kind of peace anyone hoped for. This is also the point at which he stops running away from the past, and his past. The point when he sees no future.
Food for thought: is his greatest victory over the dragon, or over himself?
(Typing this made me think of Terminator...
But it makes sense. To destroy further effects of Morgoth's curse or his own pride or whatever, Turin had to destroy himself...)
But for a more appropriate analogy, think Boromir.