I've read Doubt before, and it's more along the lines of a psychological thriller a la Saw (the first one, not the crappy higher-budget sequels), definitely got that 'distrust' thing happening, much like in Battle Royale for instance, but neither really fit what I'm looking for. Still, good reads.

I'll check out Alive! now since it's only one volume so it should be a quick read, and it's a public holiday.

________________
If you were to go there and come back to me hurt, I will take your place.. and pull everything you hate.. into destruction...
I will erase anything that hurts you.. from the face of this world.

Hellsing is like survival horror (monsters, ambushes, BFGs) without the so much "running for your life" bit as all the characters are super powerful. Along those line Jack Frost could be survival horror, but I've only read about 6 chapters of it.
Ningyou Kyuutei Gakudan is a shoujo, but it does have zombies (disease version) and involves killing zombies, though the survive part is missing as it's more about the world's political intrigue in relation to the appearance of zombies.
Emerging is a manga about trying to survive a deadly disease that spreads through Japan, but there aren't very many action parts.
Loop is a oneshot about someone surviving their own murder for the first time out of one hundred.
Bokurano is about surviving the annihilation of a world by piloting a giant robot, it's a bit more psychological than horror, but there is lots of survival involved in the story.

Second King of Thorns, first thing I thought of until I saw it was already on this list.

just adding Cradle of Monsters to the list for my own benefit. and Hohzuki Island I'd given a shot before, but dropped. I'll probably give it another try soon.
any new suggestions?

________________
If you were to go there and come back to me hurt, I will take your place.. and pull everything you hate.. into destruction...
I will erase anything that hurts you.. from the face of this world.

Dead Winter is an American comic not a manga but it's still really good.
http://deadwinter.cc/page/001.htm