Manned missions have totally required an escape system of some sort. So when you know the rocket isn't going to make it, you can let the crew escape.
In it's current design, there's no way to do that. Which is also why starship can be a lander on the moon, but it's crew will board after it gets to orbit (for now, at least).
In it's current design, there's no way to do that. Which is also why starship can be a lander on the moon, but it's crew will board after it gets to orbit (for now, at least).