Still, if "just" some goal-conflicting emails are enough to elicit this extreme behavior, who knows how many less serious alignment failures an agent might engage in every day? They absorb so much information, it's bound to run into edge cases where it's optimal to lie to users or do some slight harm to them.
Given the already fairly general intelligence of these systems, I wonder if you can even prevent that. You'd need the same checks and balances that keep humans in check, except of course that AIs will be given much more power and responsibility over our society than any human will ever be. You can also forget about human supervision - the whole "agentic" industry clearly wants to move away being bottlenecked by humans as soon as possible.