Radius of a Player to a block?

I have tried every radius like script to magnitude to finding the nearest torso. I'm trying to make a script which if a player gets inside of a certain radius to a block it will give them a GUI, Make them speak and give them an item but this script wont work. (BY THE WAY, this is a SCP script called SCP-3020 - Depression so don't mind the text)

function findNearestTorso(pos)
	local list = game.Workspace:children()
	local torso = nil
	local dist = 50
	local temp = nil
	local human = nil
	local temp2 = nil
	for x = 1, #list do
		temp2 = list[x]
		if (temp2.className == "Model") and (temp2 ~= script.Parent) then
			temp = temp2:findFirstChild("Torso")
			human = temp2:findFirstChild("Humanoid")
			if (temp ~= nil) and (human ~= nil) and (human.Health > 0) then
				if (temp.Position - pos).magnitude < dist then
					torso = temp
					dist = (temp.Position - pos).magnitude
				end
			end
		end
	end
	return torso
end


while true do
	wait(0.1)
	local target = findNearestTorso(script.Parent.Top.Position)
	if target ~= nil then

		targ = target
		hum = targ.Parent:findFirstChild("Humanoid")
		if (hum == nil) then
			script.Parent.Head.Fail:play()
		end
		local char = hum.Parent
      	 	local plr = game.Players:GetPlayerFromCharacter(char)
      	  	local Lonely = plr.PlayerGui.Lonely

		wait(40)
		
		enabled = true
	end
end

Using this script I try to make it so it makes them speak.