How to prevent ipair loops freezing functions?

The reason it is freezing (I think) Is the script is waiting for Torso and HumanoidRootPart in the model which does not contain them (Not Character model), so it will stop the function forever. So there is 2 way to fix it is to change WaitForChild to FindFirstChild

function Shoot()
    for i, v in ipairs(game.Workspace:GetChildren()) do
        torson = v:FindFirstChild("Torso") or v:FindFirstChild("HumanoidRootPart")
    end
    script.Parent.Blast:Play()
    local bullet = Instance.new("Part",workspace)
    bullet.Size = Vector3.new(0.1,0.5,0.1)
    bullet.BrickColor = BrickColor.new("Gold")
    bullet.Velocity = myTorso.CFrame.lookVector * 400
    bullet.CFrame = CFrame.new(script.Parent.Unit1.Position, torson.Position)
    bullet.CanCollide = false
    bullet.Touched:Connect(function(obj)
        if not obj:IsDescendantOf(script.Parent) then 
            local human = obj.Parent:FindFirstChild("Humanoid")
            if human then
                human:TakeDamage(45)
            end
            bullet:Destroy()
        end
    end)

    game:GetService("Debris"):AddItem(bullet, 5)
end

Or add a WaitForChild timeout

function Shoot()
    for i, v in ipairs(game.Workspace:GetChildren()) do
        torson = v:FindFirstChild("Torso",2) or v:FindFirstChild("HumanoidRootPart",2) -- The script will skip it if it cannot find after 2 sec
    end
    script.Parent.Blast:Play()
    local bullet = Instance.new("Part",workspace)
    bullet.Size = Vector3.new(0.1,0.5,0.1)
    bullet.BrickColor = BrickColor.new("Gold")
    bullet.Velocity = myTorso.CFrame.lookVector * 400
    bullet.CFrame = CFrame.new(script.Parent.Unit1.Position, torson.Position)
    bullet.CanCollide = false
    bullet.Touched:Connect(function(obj)
        if not obj:IsDescendantOf(script.Parent) then 
            local human = obj.Parent:FindFirstChild("Humanoid")
            if human then
                human:TakeDamage(45)
            end
            bullet:Destroy()
        end
    end)

    game:GetService("Debris"):AddItem(bullet, 5)
end

Hope that helped