Remember that processes inherit the restrictions of their parent process.
So if you can "execute some arbitrary code", you can already do everything that you could do by spawning a shell. The danger is when there is a privilege *granting* mechanism : suid, filesystem caps, and some selinux policies. That isn't present AFAIK.
This is only about restrictions. What is very interesting is the signed binary thing: even if you mount the filesystem on another machine and bypass filesystem security, you won;t be able to replace a choice binary with an updated or modified version.
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