I'm pretty sure I can b0rk the system by interrupting the upgrade in an inconsistent state. Or maybe inject some fun environment variables into the `apt-get` context. And I think you can launch the shell during conflict resolution for conffiles, giving you instant full access to the whole system?

A more robust design is to have a systemd one-shot unit that users can activate (via a trigger file or sudo).

So my point still stands and your example illustrates it perfectly. Either you use `sudo` for full root access or for something entirely trivial.