She’s probably thinking that the nebulizer is a threat, but not an immediate one, since it hasn’t done anything to her.
The fact that she didn’t hide suggests that it isn’t the sound itself that bothers her, but what it represents. Eventually, she’ll realize that it doesn’t represent anything harmful, and she’ll ignore it.
Maybe she was chased by someone with a vacuum, or something just as sinister. I had to put the late Tokyo Rose (black and gray tabby with blue eyes) in the bathroom when I vacuumed or she went berserk. She was that way with plastic grocery bags, too, so when I bought groceries, I always put her in the bathroom before I unloaded the bags.
Poor ol’ soul was blind. There is a long story behind that, but I rescued her from the family that tormented her. She had big mats of hair on her back and sides, and my roommate said she couldn’t get close to the cat to cut them off. She hated the cat and Tokyo knew it.
Tokyo came into my room to check it out...sniffing along the walls and as soon as she got to the sofa where I was lying down watching TV, she floated up onto my chest and began to purr. The roommates daughter was passing my room and looked in, saw the cat and said, “MOM! MOM! COME AND SEE THIS!” Roomie saw me with the cat on my chest and said, “That’s it. Take her with you whenever you move out.”
A little bit later that day, I cut the mats off her back and sides. When I moved out, I took her, and every day, when I went to work, she would sleep on my pillow until it was time for me to come home, and then she would lie on the mat in front of the door, and give a nonchalant stretch when I came in. I miss that ol’ gal, even today.
Sparkle will just need time, that’s all. She can have all the time she needs.