I will try to add a drawing I made several years ago, but this conceptual design is easy to visualize.
Basically this is a rocket launch double escape system conceptual design. The double escape system may also be used for re-entry.
The Mercury, Gemini, and Apollo rockets all employed a launch escape system. That system was basically a small rocket attached to the top of the rocket that could launch and free the space capsule from the main rocket in the event of main rocket failure.
Similar to automobile design evolution in that a car has seat belts and then later desings add the air bags, this conceptual rocket design uses the previous launch escape system but then adds individual pod / enclosed ejection seats for each individual astronaut.
In other words, two independent launch escape systems are built into the rocket. The early small rocket on top launch escape system may be employed to remove the enite capsule from the main rocket, or individual enclosed rocket ejection seats may be used to eject each Astronaut individually.
These individual enclosed ejections seats would be similar to designs that have been around since the 1950s for used in high altitude bombers.
For some failure modes, the enclosed indivual ejection seats may be the primary system, work better, etc., or vice versa. In any event if one system does not work, the other system is available as a back up system, increasing the overall launch escape reliability and probablility of success.