bacsically if you are in spectator mode, you can die with /kill @e

steps to recreate: 

make a world with "spectator mode" toggle on,

go into spectator mode (aka /gamemode spectator),

and type in chat /kill @e

boom, you're dead in spectator mode

Edit: i know that you can do it in java, but in bedrock, you cant die in creative with /kill @e. this justifies that 1 comment. also in the duplicate, it says this too.