Drill......

Hello, so i saw a video about the drill plugin ()
and i told myself that i can make myself this plugin.
but i dont know why its doesnt work good.

The code:

Code:

    public void start(Player p,Location loc) {
       
            new BukkitRunnable() {
               
                int i = 0;
                @Override
                public void run() {
                    i++;
                    if(loc.subtract(0, i, 0).getBlock().getType() == Material.BEDROCK) {
                        for(int test = 0; test < i; test++) {
                            loc.add(0, i, 0).getBlock().setType(Material.DIRT);
                            p.sendMessage("Drill has been over!");
                            cancel();
                        }
                        return;
                    }
                    if(loc.subtract(0, i, 0).getBlock().getType() == Material.AIR) {
                        loc.subtract(0, i, 0).getBlock().setType(Material.COBBLE_WALL);
                        return;
                    }
                    String nameOfBlock = loc.subtract(0, i, 0).getBlock().getType().toString().toLowerCase().trim();
                    Material id = loc.subtract(0, i, 0).getBlock().getType();
                    loc.subtract(0, i, 0).getBlock().setType(Material.COBBLE_WALL);
                    p.sendMessage("Just broke " + nameOfBlock);
                    p.getInventory().addItem(new ItemStack(id));
                    p.sendMessage("" + i);
                }
            }.runTaskTimer(this, 20, 20);
       
    }
   
    @EventHandler
    public void drill(PlayerInteractEvent e) {
        if(e.getAction().equals(Action.RIGHT_CLICK_BLOCK)) {
            if(e.getClickedBlock().getType() == Material.FENCE && e.getClickedBlock().getRelative(BlockFace.EAST).getType() == Material.IRON_BLOCK && e.getClickedBlock().getRelative(BlockFace.WEST).getType() == Material.IRON_BLOCK && e.getClickedBlock().getRelative(BlockFace.UP).getType() == Material.REDSTONE_TORCH_ON) {
                Location loc = e.getClickedBlock().getLocation();
                e.getPlayer().sendMessage("The Drill is on, please wait 30 seconds.");
                start(e.getPlayer(), loc);
            }
        }
    }

its breaking i dont know why 5 blocks or 6 or 7 like a random number under the drill....

EDIT by Moderator: merged posts, please use the edit button instead of double posting.