Started to play dead is dead on hardest difficulty got to level 9 went inside some Rangers office were bunch NCR soldiers were killed steeped on a bomb instant kill with full health of 300. my question, is it even worth's playing dead is dead in FLNV and are there many places were you get instant kills that are not enemy related?

ps

my bad on misspelling instant

Yes it's worth indeed.
Traps are also your enemy.
It's one of the reasons for you to always cautions in DiD playthrough.

i guess i will have to be more careful in next playthrough

but is it even possible on highest difficulty