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.