That's not really how Living Dead works and it is better if you want a call-out macro for Living Dead/Walking Dead to break it into two macros. It's annoying, especially considering how the other tanks have much more straight forward "Invulnerable" moves, but it is what it is even if it sucks.
When you activate Living Dead you have 10 seconds to drop to 0 hp or else Living Dead goes away and does nothing. You DO NOT want to be healed during that time at all as it could result in wasting the ability.
If you drop to 0 hp during those 10 seconds, you don't die and the Walking Dead state activates during which you cannot drop below 1 hp (i.e. can take damage but can't die) for 10 seconds but require to be healed for an amount equaling your total HP, not to be confused with needing to be healed to full health, before that time elapses or you will die. If you get healed the necessary amount, Walking Dead goes away which stops the "you die" effect but also gets rid of any time left on the "you can't be killed" effect.
It's really best to break it into two macros. The first one activates Living Dead, calls out that you used it and says to not get healed until Walking Dead gets activated. The second one gets used when Walking Dead gets triggered to call out that it is now active and that you need to be healed for 100% of your health within 7-8 seconds (I recommend saying a shorter amount instead of 10s so that healers don't wait until the last second and you die because of it).
@OP
Good luck with the macros. I have had two macros for calling out Living Dead and Walking Dead since DRK was released and I have yet to get a DF healer that handled Living Dead properly even when my macros tell them what to do. They always end up healing right away causing Living Dead to be wasted or I end up getting killed by Walking Dead because they didn't heal me after Walking Dead activated. I pretty much gave up relying on Living Dead in DF PUGs a long time ago.