The often-stated safety measure of shutting down a liquid-fueled engine is less comprehensive than first appears. If the Saturn V had a single engine failure during the first 14 seconds of flight, thrust:weight ratio dropped below 1:1 and it would fall back onto the pad. All five engines had to work perfectly, at least that long.
However I think Saturn V had much more realistic abort options over the Shuttle. A solid fuel rocket motor was attached directly to the nose cone that contained the command module. The command module could therefore be dragged clear by this (to safe parachute and splashdown height).
Once the emergency escape rocket was jettisoned the vehicle was high enough for the whole Command/Service module to power itself clear of the main structure.
The lunar lander was of course another story. Scarily lacking in any contingency a long long way from home.