The Acharaonim discuss whether a person is allowed to put himself in a ספק סכנה to help the רבים. One of the sources they bring is the Mishna in Makos 9b which states that the killer is not allowed to leave the עיר מקלט even if the Jewish People need him even if he is the greatest General around. The Tiferes Yisrael on that Mishna asks why not? Pikuach Nefesh is דוחה everything except the big 3 aveiros, he leaves the question בצ"ע. From here the אור שמח extrapolates that a person is not chayav to put himself in a ספק סכנה to help others. The Tiferes Yisrael (and many other Acharonim) clearly argue.
The Aruch Hashulchan discusses whether he is allowed to volunteer and thinks that he can. In other words while there may be no חיוב for him to put himself in a dangerous situation he can certainly volunteer.
The Minchas Chinuch discusses the case of soldiers and war and states that since soldiers are killed in war on one hand and Hashem commanded us to fight wars on the other hand, by definition war must be exempt from the general rules of pikuach nefesh and therefore these rules don't apply.
RHS holds that we have been in a state of war with the Arabs since 1948 and therefore in EY today the situation is one of wartime and therefore we need to apply the position of the Minchas Chinuch and Pikuach Nefesh does not necessarily apply. R' Yaakov Kaminetsky made a similar comment about people living in Gush Katif (see this post More Charedi censorship):
The settlers in Gush Katif asked R' Yaakov Kamenetsky if they are allowed to live there, maybe they should move because of Pikuach Nefesh? He answered that it is a milchemes miztva (and therefore there is no halacha of pikuach nefesh like the Minchas Chinuch, my interpretation).
Based on the above, there are a number of reasons why a person can live in a dangerous place in EY.
1. According to RHS and RYK we are in the middle of a war and therefore the rules of pikuach nefesh don't apply.
2. According to many Acharonim a person is allowed to put himself in a ספק סכנה to help the רבים
3. According to the Aruch Hashulchan a person can volunteer to put himself in a ספק סכנה to help the רבים