If something would have gone wrong after a successful Moon landing requiring to ascent as soon as possible, what about the launch window for the lunar rendezvous maneuver? Could they ascent at any time or only in a short interval of the orbit period of the Command Module?
One lunar orbit of Apollo 8 took about two hours with 45 minutes without radio contact to Earth. See the answer to this question for the average orbit periods of all Apollo lunar orbits very close to two hours.
The launch window for LM might have been about 15 to 30 minutes every two hours, is that right?