if anything bad happens, the capsule with astronauts can safely detach from the rocket. New innovation by Musk Pretty barbaric that they never implemented that safety feature back then
You might see the vapor trail. On night launches, i can see a tiny fireball from my place. I was going to see the launch but got caught up at work. There was suppose to be a lot of rain and with Trump in the area, I decided to hope it was scrubbed. They waited hours after the initial launch window for the Falcon Heavy. That was a hot day on the beach waiting for that launch. With all eyes on, they could push it back later in the evening if need to be. Right now its sunny here in Orlando so its looking good.
there was definitely such a thing on apollo. Note the red tower on top of the command module. It could pull the capsule away from an exploding Saturn V. The Soviets copied the system and actually saved two cosmonauts lives. They flew to Houston to thank the design engineers.