You can survive quite powerful tornadoes in an interior bathroom. House could be gone and you could survive. You’d have a good chance in ALMOST anything in a bathtub that you’ve pulled a mattress on top of.
If it’s an iron tub . They did a show of Mythbusters on that.(the ‘Lethal Weapon’ movie myth)
Downstairs bathroom is a half bath but is safe room where it is. Have two large sofa cushions I put over Yorkie and me, plus I have that helmet. If the bathroom is still standing afterward, puppy and I have 3 days of food and water in backpack in there with us.
That's true up to and including an EF3. An EF4 is probably too much for that situation, and there would be roughly zero chance of survival in an EF5 (but EF5 damage is very difficult to survive in a house, even in a basement).