[1.15.2]always display gui and kill player

[Mower]

I'm trying to display a simply gui about player's thirst level. It goes from 100% to 0% within 5 minutes. The problem is, I can display it only when I click an item. I'd like to display it without any items, but didn't find the solution. The second problem is, I don't know how to kill the player. What's the correct code to do it in 1.15.2?

Here's my gui:

public class ThirstScreen extends Screen {
    MyTimer timer = new MyTimer();
    private static final int WIDTH = 192;
    private static final int HEIGHT = 192;
    private ResourceLocation GUI = new ResourceLocation(VenonatMod.MOD_ID, "textures/gui/thirst_gui.png");

    public ThirstScreen() {
        super(new StringTextComponent("Thirst"));
        MinecraftForge.EVENT_BUS.register(this);
    }


    @Override
    public boolean isPauseScreen() {
        return false;
    }

    @Override
    public void render(int mouseX, int mouseY, float partialTicks) {
        int relX = (this.width - WIDTH) / 2;
        int relY = (this.height - HEIGHT) / 2;
        this.minecraft.fontRenderer.drawString(
                    "Thirst level: " + timer.getCountdown(),
                    relX + 200,
                    relY + 150,
                    0xffffff);
    }

    @SubscribeEvent
    public void onRenderOverlayText(RenderGameOverlayEvent.Post event) {

        if (this.minecraft != null && Minecraft.getInstance().currentScreen instanceof ThirstScreen) {
            RenderSystem.color4f(1.0F, 1.0F, 1.0F, 1.0F);
            this.minecraft.getTextureManager().bindTexture(GUI);
            int relX = (this.width - WIDTH) / 2;
            int relY = (this.height - HEIGHT) / 2;
            this.blit(relX, relY, 0, 0, WIDTH, HEIGHT);
        } else {
            MinecraftForge.EVENT_BUS.unregister(this);
        }
    }
}

 

and here's my right click action:

    @Override
    public ActionResult<ItemStack> onItemRightClick(World worldIn, PlayerEntity playerIn, Hand handIn) {
        Minecraft.getInstance().displayGuiScreen(new ThirstScreen());
        return super.onItemRightClick(worldIn, playerIn, handIn);
    }

As you can see, it displays with right click on the item. What should I change to display it always?

 

And the second question about killing someone. What's the correct code to do that?

Edited April 16, 2020 by Mower

[Mower]

Thanks for the answer, I can kill the player now, but I don't really understand your explanation about the hud. Could you show it on my code please?

[Mower]

You mean remove this whole part? 

    @SubscribeEvent
    public void onRenderOverlayText(RenderGameOverlayEvent.Post event) {

        if (this.minecraft != null && Minecraft.getInstance().currentScreen instanceof ThirstScreen) {
            RenderSystem.color4f(1.0F, 1.0F, 1.0F, 1.0F);
            this.minecraft.getTextureManager().bindTexture(GUI);
            int relX = (this.width - WIDTH) / 2;
            int relY = (this.height - HEIGHT) / 2;
            this.blit(relX, relY, 0, 0, WIDTH, HEIGHT);
        } else {
            MinecraftForge.EVENT_BUS.unregister(this);
        }
    }

 

I don't really get how it should help. I've tried to add 

Minecraft.getInstance().displayGuiScreen(new ThirstScreen());

under my 

public class ThirstScreen extends Screen {

 

but it doesn't display it.

[Mower]

and how can I do that?

[Mower]

Here's what I use now:

    @SubscribeEvent
    public void pickupItem(EntityItemPickupEvent event) {
        Minecraft.getInstance().displayGuiScreen(new ThirstScreen());
    }

of course this one is called only if I pick up something. So I have 2 questions: What should I use instead of EntityItemPickupEvent to always display it? And the second, how can I turn off the mouse when its being displayed?

Edited April 16, 2020 by Mower

[Mower]

But how else should i Write "thirst level" to the screen?

 

[Mower]

Can you please show it on my code? I've been sitting here for hours now but still no clue.