entities - damage if func_pointparticles

hey,

I have created a small map with two func_pointparticles entities.
Both use as effect pipe_smoke.

Actually my idea is that the player gets hurt if the particles are emitted.
First func_pointparticles is combined with trigger_swamp.
I tried to activate/deactivate trigger_swamp by modifying its keys dmg and swamp_slowdown via target_spawn entities.
Second func_pointparticles is combined with trigger_hurt, which should be activated/deactivated via relay_activate and relay_deactivate.

But both fail

I added a pk3... solution expected
  testent.pk3 (Size: 4.21 KB / Downloads: 5)

Note to mappers who might help with this: if you find that the approach *should* work but doesn't, please say so and we can file a bug report. It seems strange to me that trigger_hurt wouldn't be affected by relay_(de)activate.

I once wanted to make a "trap map". Here's how I did it: you push a button, some "gas holder cannisters" open up, green particles are emitted, and a trigger hurt is activated.
I pasted the relevant part into this map, I hope it still works, I didn't tested:
http://akion.planetnexuiz.de/toxicparticles.map

The map and it's effects work fine, thanks C.Brutail
But you do not activate/deactivate trigger_hurt. It's connected to func_door and misc_follow. If the door moves in direction of z-axis, trigger_hurt does, too.
Players are able to touch it and get hurt.
It works and I will use the same principle, but i would like to know how you can toggle the status of trigger_hurt or modify the entity keys of trigger_swamp via target_spawn.

Is it possible to toggle an event randomly, or on equal intervals?