Battle Royale

Story/background
42 unlucky students from a high school in Japan have just won an impartial lottery.
The prize? One week on a small island hidden by the government.
This island is where everything will take place, it’s the chosen spot for each years “battle royale”
You are one of these students and chances are, you will die.
I highly recommend watching this instead of reading what’s in the next section!
(part 2 of Battle Royale, the explanation it gives starts at 3:05)
(I quoted it nearly line for line, but its better if you watch it. Just remember the 3 day time limit has been upped to 1 week.)
http://www.youtube.com/watch?v=JG5CDjJ45qY
The right way to fight the battle royale!
By the BR act committee.
(insert overly happy Japanese girl voice here)By the BR act committee.
Hello everyone in class b!
You are the lucky class chosen for this year’s battle royale!
CONGRATULATIONS!
Now I’m going to explain the rules for you
Listen well to fight right and with gusto.
You are on a deserted island that looks like this
(

its about ten kilometers around.
But we evacuated everyone so its empty. The island is divided into many zones.
Every six hours your teacher’ll broadcast an update.
About which zones are becoming danger zones. If you are in those zones you should leave quickly.
Because the danger is…………..
OK, about the necklaces you are wearing.
They are 100% water proof and shock proof and permanent!
It monitors your pulse, informing us of your location and movements
So if you linger in a danger zone.
Or cause trouble we can identify you and transmit radio waves
That trigger and alarm and boom! It explodes!
If you try to rip it off it explodes too. So promise not to try that, OK?
Oh, I forgot one important thing there’s a time limit on this game: 1 week!
If we haven’t gotten 1 winner after 1 week all the necklaces automatically explode!
And no one wins. As long as we’re here, lets fight hard. So that doesn’t happen!