Is "While I was cooking, she cleaned the room" correct?

Why

Ishaan's rule may come from noticing the interrupted-action pattern, where only ONE verb (the background one) takes continuous while the other stays simple past. But that pattern only applies when one action is a sudden event cutting into a longer one — here, cooking and cleaning are both long, ongoing activities stretched out over the same period, side by side, not one interrupting the other. When two actions are genuinely happening at the same time as each other, both stretched out together, English marks BOTH with the continuous tense, showing that neither one is the sudden interrupting event. Test: picture the scene directly — you were cooking, minute by minute, while, in parallel, she was cleaning, minute by minute — neither action is the short, sudden one, so neither should be forced into the simple past. His teacher is right: two genuinely simultaneous ongoing actions both take the continuous tense; only the interrupted-action pattern forces just one of them into the simple past.