I attempted to Re-construct the event and nothing happened besides my Hunger/Thirst Level going down. Will attempt in a more similar situation or with a more dense population.

As far as I know there is a bug that sometimes gunshots are not hearable.
I'm 99% sure there was no other player around as I did not hear any footsteps or any other sound and there just was 2-3 other players on the server (I've checked before entering Elektro and 2 times while in the city just to be prepared).
Only explanation (other than: tuna killed me) could be someone spawned behind me outside my field of view, gave me a headshot but the shot itself was not hearable.

/edit: I'm still pretty new to the game so I'm not sure if a headshot leads to instant death or puts you in unconsciousness state before.

See issue #5169, sounds like a similar issue.

tks @ Richa678 ...so how does this work here? Do I post my issue into the other thread so everything gets collected at one place?

/edit: posted to the other thread as that one seem to have more attention already.

Closing as duplicate of #0005169: Instant Death Glitch (Inside Buildings on 2nd or higher level)

Please vote up the original issue to increase visibility, add any extra information in the notes section, and monitor it for further developments.

Thanks