Ohhhhh......please don't teach your cats that washers/driers are fun kitty hangouts. You have orange cats, and it's especially true for black cats, but any cat can get acceidently not seen. Then you close the washer, turn it on, and THEN the cat starts making noise. Except, the foor is locked, and filling with water. Even assuming you know which breaker to flip, or even if you just flip the main switch and cut power to the whole house, it still won't unlock the door. And there's still water in there. Hopefully you caught it before there's enough water to drown the cat. Still though, even if it's only belly high, cats still hate that. Plus now there's soap all over her, and you'll need to give her an actual bath, so she isn't licking soap, or worse, bleach, off her cat hair.
My grandma had a story about how my dad killed a cat in the 60s just by turning on the drier. My dad REFUSED to get a cat my whole childhood because of it. And I love cats. He was afraid I'd kill it. He also refused to let me do laundry.