Based on the fact that your roommate did not wake up even after you knocked over the vase, they are probably experiencing slow-wave sleep.
This is a stage of sleep commonly referred to as Phase 3 sleep. At this stage, a human is deeply asleep and will not hear much of movement around them.
Because your friend was at this stage, they did not hear the vase being knocked down.
In conclusion, this is slow-wave sleep.
Find out more on stages of sleep at https://brainly.com/question/18474100.
