NASA has shown the world a rescue system that can be used when something goes wrong shortly before launch. If there is no time to disappear from the rocket in the usual way, the crew can board a kind of rescue cableway at the top of the ramp, which will transport the astronauts to safety. The whole process is a matter of tens of seconds. In the link below the article, you can watch a video that demonstrates the entire process of evacuation by cable car.
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On April 3, @NASA and @SpaceX conducted an emergency egress exercise at Launch Complex 39A at @NASAKennedy.
This demonstration was completed to ensure the crew & support teams can quickly evacuate from the launch pad in the unlikely event of an emergency: https://t.co/5xYN51WHGp pic.twitter.com/75LTRoyMKA
— NASA Commercial Crew (@Commercial_Crew) April 7, 2020