I personally wait Living Dead to have 5s left and do Emergency Tactic + Adlo + Recitation + Excog + 1 lustrate, that's usually enough.

However, any remotely competent DRK would have Abyssal Drain up and used at this point to eleviate the issue. (maybe you're unlucky and got Darknoobs)

Don't forget that during the first 5s, your fairy does heal, if you add up the HoT, over the course of those 10s she'll do a good 30k heal on the tank. it's really not that hard IF you know it's coming (and any good DRK will tell you "LD next pull" or something