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.