I always launch using the mouse and the fire button on the screen to avoid the return launch.
The 'q' for open doors does work, but the tubes have a habit of closing again when you select another tube. So if you select all tubes and hit open, then go back to single selection and tube 1, you might find the other three closing. Can't remember exactly what cause it (new selection or firing) but just play around with it and you'll find it quickly enough. Deal with it by just opening the tube I'm using at the time, as soon as it's fired I select the next tube and hit 'q' again so it's opening while I set my next shot. When in doubt, aways hit 'q'
T.