Why does the server seems to fire several times?

So these two scripts work together to fire a missile. Don't worry about the missing values. My problem is that more than one missile is fired when I press "w" once, and when they stack on top of each other they explode the cannon.

Local Script:

mouse.KeyDown:connect(function(key)
	if key == "w" and currentFighter.Seat:FindFirstChild("SeatWeld") and currentFighter.Seat.SeatWeld.Part1.Parent.Name == plr.Name then
		game:GetService("RunService").RenderStepped:connect(function()
		local mb = currentFighter.Body.BodyVelocity
		mb.Velocity = currentFighter.Body.CFrame.lookVector * 90
		end)
	end
end)

Server Script:

seat.ChildAdded:connect(function(plr)
	fe.OnServerEvent:connect(function(lplr, type)
	if type == 1 and seat and seat:FindFirstChild("SeatWeld") and seat.SeatWeld.Part1.Parent:FindFirstChild("Humanoid") then	
		p = Instance.new("Part")
		p.Name = "Missile"
		p.Parent = workspace
		p.CanCollide = true
		local m = Instance.new("SpecialMesh")
		m.MeshId = "http://roblox.com/asset/?id=2251534"
		m.Parent = p
		local spawnPos = body.Position + Vector3.new(0,-11,0)
		p.Position = spawnPos
		p.Rotation = body.Rotation
		p.Velocity = body.CFrame.lookVector * 1000
		local col = script.Collision:Clone()
		col.Parent = p 
		col.Disabled = false
			wait(.2)
		end
	end)
end)