Humanoid always falls when Unanchored?

I have a zombie which is anchored when spawned, but after 3 seconds it gets unanchored and just falls down. I want the zombie to instantly start walking when he gets unanchored. I am trying to make an animation, where a zombie comes up from the ground, like in the game Zombie Attack. This is the code I have now:

function SpawnZombie()
	local zombieTorso = script.Parent.HumanoidRootPart
	
	--zombieTorso.Anchored = true
	script.Parent.Torso.CanCollide = false
	script.Parent["Left Leg"].CanCollide = false
	script.Parent["Right Leg"].CanCollide = false
	
	for i = -5.5, 4.5 do
		zombieTorso.CFrame = CFrame.new(zombieTorso.Position.x, i, zombieTorso.Position.y)
		wait(0.1)
	end

	--zombieTorso.Anchored = false
	script.Parent.Torso.CanCollide = false
	script.Parent["Left Leg"].CanCollide = true
	script.Parent["Right Leg"].CanCollide = true
	
	zombie:MoveTo(Vector3.new(0, 0, 0))
end

Make sure the CanCollide Property is set to true in each part of the zombie.

Also, to make any humanoid walk, you would to use the MoveTo function of Model.

Model:MoveTo(positionwhereyouwanthimtomove)

Try using a Weld Script.