How to kill player if they aren't standing on a part?

local VanFloor = game.Workspace.ucb.vantruck.VanFloor

VanFloor.Touched:Connect(function(itemTouchingPart) print("Item touching part: ", itemTouchingPart)

if(itemTouchingPart.Parent and game.Players:FindFirstChild(itemTouchingPart.Parent.Name))then
    print("There is a player touching the part!") else v.Character.Humanoid.Health = 0
end 

My problem is in v.Character it says v is unknown, how do I define v?,

You basically want to kill a player if their item is touching a part, right? this is a script to kill the player if either that player or their item is on a part;

-- in this example, MyKillBrick is the part you want to do the killing
function onTouched(part)
	local hum = part.Parent.Humanoid
	if hum == nil then
		local tool =  part:FindFirstAncestorWhichIsA("Tool") 		
		if tool ~= nil then
	hum = tool.Parent.Humanoid 
		end
	end
	print("Good So Far")
	wait()
	if hum then
		hum.Health = 0
	end
end
MyKillBrick.Touched:Connect(onTouched)

If this doesnt work or isnt what you intended, comment on this and I'll see what I can do. If it is good, you can accept my answer ;)

IGNORE EVERYTHING BEFORE HERE

EDIT: Try this. Put these 1st script in the part you want and put a BoolValue named "TouchingFloor" in StarterCharacterScripts 1st Script:

function onLeft(part)
	local hum = part.Parent.Humanoid
	if hum == true then
		part.Parent.TouchingFloor.Value = false
	end
end
function onTouched(part)
	local hum = part.Parent.Humanoid
	if hum == true then
		part.Parent.TouchingFloor.Value = true
	end
end	
script.Parent.TouchEnded:Connect(onLeft)
script.Parent.Touched:Connect(onTouched)	

Here is the second script. Put this also in StarterCharacterScripts:

while true do
	wait(0.5)
	if script.Parent.TouchingFloor.Value == false then
		repeat
			x= x + 1
			wait(0.1)
		until x == 5 or  script.Parent.TouchingFloor.Value == true
		if script.Parent.TouchingFloor.Value == false then
			script.Parent.Humanoid.Health = 0
		end
	end
end

This will Punish the player for having none of them touch the floor (or whatever part) for over a 1/2 second. I did this because their animation might have them leave the floor for a split second. Respond if this doesnt work and i'll get back to you ASAP