If you are referring the 30 seconds to kill time, that would be holding it wrong. As long as your process is PID 1, you can rig up your own process exit handlers, which completely resolves the problem.

Many people don’t run the main process in the container as PID 1, so this “problem” remains.

If it’s not feasible to remove something like a shell process from being the first thing that runs, exec will allow replacing the shell process with the application process.