The type of 1911 safety matters...
I carry a 1911 frequently, but not exclusively. I have thought about the issue of failing to release the thumb safety when under pressure. I try to guard against this by practicing the release of the safety, as well as the re-application of the safety before re-holstering the gun. People have been known to shoot themselves with their 1911 when holstering because they didn't set the thumb safety first. Even when shooting at the range without use of a holster, I will load the gun, chamber a round, set the safety and put down the gun briefly. Then I pick it up, release the safety and begin shooting. You want the manipulation of the safety to be second nature and firmly ingrained in your memory.
I also like to use a 1911 with a fairly stiff safety that "clicks" audibly when activated. Some 1911 safeties have an extended lever and rather light action, such that the safety goes off too easily to suit me. I want to know that the safety will stay off or stay on when I want it to do so. I especially like the traditional Colt safety because it doesn't have the extended lever and operates fairly stiffly. My favorite 1911 for carry is a Colt Defender with a traditional safety, as shown below in "on" position.