The suttas contain account of arahants who have committed suicide, so by inference, it's possible that suicide could be done without a defiled mind. You mention kamma in your post. If suicide, a volitional action, is done without a defiled mind (in other words, the action was done from a mindstate rooted in generosity, lovingkindess and/or wisdom) then it needn't be considered "bad kamma". However, such circumstances would of course be rare, hence why the first precept is 99.999% of the time the best course of action.
"Do not force others, including children, by any means whatsoever, to adopt your views, whether by authority, threat, money, propaganda, or even education." - Ven. Thich Nhat Hanh
"Whether I were to preach in brief, Sāriputta, or whether I were to preach in detail, Sāriputta, or whether I were to preach both in brief or in detail, Sāriputta, rare are those who understand." (A I 333, Sāriputtasutta)