Why does this script get all players who have "Arm1 in their character?

Hello

I'm going to take an extract of my script to show you what I mean.

function onClick(noot)
	local val = script.Parent.Parent.TextBox.Value.Value
	local text = script.Parent.Parent.TextBox
	val = text.Text
	local plr = game.Players:FindFirstChild(val)
	if plr and plr.Character and plr.Character:FindFirstChild("Arm1") then
		local hum = plr.Character.Humanoid
		local sta = script.Parent.Parent.Parent.status2
		script.Parent.Parent.Parent.status.Visible = false
 		sta.Visible = true
		sta.user.Text = plr.Name
		hum.HealthChanged:Connect(function(Eealth)
       		sta.health.Text = Eealth
			if Eealth == 100 then
				sta.healcolor.TextColor3 = Color3.fromRGB(16, 245, 4)
				sta.healcolor.Text = 'Health'
			end
       		if Eealth <= 50 then
              	sta.healcolor.TextColor3 = Color3.fromRGB(245,230,15)
       		end
       		if Eealth <= 25 then
             	sta.healcolor.TextColor3 = Color3.fromRGB(255,93,3)
       		end
       		if Eealth == 0 then
             	sta.healcolor.Text = 'Dead'
             	sta.healcolor.TextColor3 = Color3.fromRGB(255,0,0)
       		end
		end)
		sta.health.Text = plr.Character.Humanoid.Health
end

So this is supposed to put "Health" in a TextLabel, and change the color when the health is below 50 etc. Let's take as example

2 players, 1 just died, and it shows "Dead" in red. I go to the other player in the GUI, and in the stats it shows me his health but it's still at "Dead".

Another example this time with an explosion.

		local function onNoot()
			local e = Instance.new("Explosion")
			local ab = plr.Character.HumanoidRootPart.Position
			e.BlastRadius = 4
			e.Position = Vector3.new(ab.x, ab.y, ab.z)
			e.Parent = plr.Character.Arm1.red
		end
		sta.explode.MouseButton1Click:connect(onNoot)

Again, I press a button and the player who has the model named Arm1 in his character explodes. However, I noticed that when multiple players have the tracker, all of them explode when I only want one specific player to explode.

Please help me.