How do I kill another team if they touch something?

Lets assume the teams are called "Red" and "Blue".

door = script.Parent -- Assume this is the door/brick's location.
players = game.Players:GetChildren()

function onTouch(part)
	for i = 1, #players do
		if part:IsDescendantOf(players[i].Character) then
			return players[i]
end

door.Touched:connect(function(part)
	local player = onTouch(part)
	if not player then
		return
	end
	
	local access = player.Team == "Red" -- Lets the Red team go through the door.
	
	if access then
		door.Transparency = 0.5
		door.CanCollide = true
		wait(0.5)
		door.Transparency = 0
		door.CanCollide = false
	end
	
	if not access then
		player.Character.Humanoid.Health = 0
	end

end)

The function OnTouch part of the script checks for players and the door.Touched:connect() part activates once the door has been touched. If the player is in the Red team then the door lets them through. If they aren't then the door kills them.