For those of you who don't know how exactly to block off an area, you use a kill boundary. Go into Spawning-->Kill Boundaries-->Here you can choose your variant. This is the same with the Safe boundary. Just set it down and if you exit the area, then you must enter before the count down timer runs out. I JUST now figured this out and I haven't used a kill boundary or safe boundary but I'm pretty sure how that works.

Kill Zone will instantly kill you.
Soft Kill Zone will start the timer.

Haven't experimented with the safe zone(s) yet.

Technogician wrote:

Haven't experimented with the safe zone(s) yet.

I think a safe zone is a zone you can put within a kill zone to make it safe, IE it doesn't kill you.

In forge I usually make prisons and put a soft kill boundary in there and whoever gets trapped in my prison I tell them

" You been sentenced to prison for 10 seconds "