SCH lacks a single target mitigation ability

[AnotherPerson]

Not entirely, it can be a coding issue that is part of the balance of a job. Lets say you use living dead and your HP is exactly 10k in the normal case. If you now get 10% extra, it becomes 11k, and walking dead now triggers. If expedient ends, you have only 10k max. Lets say the 2nd healer uses benediction on you, effectively being that 100% heal. What happens?

From what I understand, Living dead only activates when you hit below 1 HP, not when you lose a certain amount of HP. Walking Dead will not trigger unless you drop below 1 HP, not when you reach 1 HP because a buff expired.
The reverse is also different - Walking dead only requires you to restore a certain amount of HP to get out of Walking dead, not reach a certain percentage of HP. Plus, the Cure Potency of Walking dead is pretty much good enough to prevent that from happening now, even if a healer benediction late, because the DRK can just attack and cover the difference if the Walking Dead debuff hasn't been removed.