I already commented about Expect elsewhere in this thread, so I should probably pipe down, but thought it might be worth it here as well because Expect has been handling these kinds of exceptions and control transfers/flows with the full power of a robust programming language for decades. You might have a look at it for ideas and inspiration.

https://en.wikipedia.org/wiki/Expect

Looks neat, thx. It is really interesting how many facets the same kind of issue can produce. I think using expect from baker is a great way to deal with some steps that are hard to automate otherwise.