getTiles return an empty array

Title says it all. I loaded my level already. Code:

PHP:

$this->getServer()->loadLevel("hny");
var_dump($this->getServer()->getLevelByName("hny")->getTiles()); //array(0)


There are tiles in the world. I checked with my MCPE and even with code:

PHP:

public function onInteract(PlayerInteractEvent $e){
        var_dump($e->getBlock()); //Chest 'block'
        var_dump($t = $e->getBlock()->getLevel()->getTile($e->getBlock())); //Returns a chest tile
}


I think this is the answer: http://forums.pocketmine.net/threads/level-getentites-returns-nothing.14141/

But what are $x and $z?

And, can I load all the chunks in a world?

Read the IRC logs from my link onwards one hour.
https://botbot.me/freenode/pocketmine/msg/57004366/
Too lazy to summarize them again

So...

$level->getChunk(6 >> 4, -5 >> 4)->getTiles()

I don't get what are chunks so... I can't understand anything, which results an unsolvable problem for me.