That's actually kind of tragic from the bird's point of view, lol. It probably thought the dryer buzzer was another bird trying to talk to it, and then you showed up making all kinds of weird noises fixing it. Now the poor thing's whole social life is thrown off. Bet it started mimicking your power drill next just to keep the conversation going.
My cousin's cockatoo picked up the exact beep of their microwave. It would mimic the sound from its cage whenever someone heated up leftovers. Took them weeks to realize the bird was doing it, not a broken machine. They started keeping the microwave unplugged just to avoid the confusion.
When you said the bird might mimic the power drill, it got me thinking about something else. What if these sounds start replacing their natural ones? A bird that learns too many machine noises might forget how to make proper bird calls. Then, if it ever meets other birds, they won't understand it. It's like learning a fake language that no one else speaks. That could leave the bird totally alone, even in a group.