I'm sorry, I think I'm misunderstanding the OP
I used to be an effective DRK when it originally came out. I reread the skill in the wiki.
If I'm reading it correctly Living Dead could have a total up time of 20s between Living Dead(10s) and Walking Dead(10s).

Is the issue, you want the healer to focus kill until the last 5s of Walking Dead, but they seem to just let you die?
Or
They never let you get into Walking Dead making the skill uptime only 10s instead of the protentional 20s?