The problem of anticipating situations lend to superficial solutions. A student once asked what is the best solution if a knife has been put near your neck while you were asleep. I tried my best how to answer it as appropriately as possible. Real problem-solving must utilize the scientific method of identifying all variables to a given phenomena and evaluate and analyze the end result. In the question given, a self-defense trainer must get their students to realize the other variables aside from the fact of the knife and the "victim" being prone and asleep.
What other variables could there be? We must realize that all phenomena is the result of processes. What led to the knife pointing are a series of events and factors. Was the door to the room locked before the "victim" slept? Does it have a spare key? Is the attacker known to the victim and has access to the room? Variables such as these could lead to the said incident. Therefore avoiding such occurrence will rely on the negation of these variables.
Rather than concentrate on how to thwart the knife attack, an ounce of prevention goes a long way. Indeed, personal threat awareness is the essence of an efficient self-defense system. You defeat the core concepts of Waya-an if after training you enter a dark-lit alley because you are self-assured you can handle any kind of mugging.
Threat awareness, tactical avoidance and tactical contingency response are necessary components of a self-defense system, not just physical attributes and counter-conflict training.
However, we must also realize that social demography plays a role on individual security. The poor cannot afford to have a panic room, much less a real house. The poor lives in crime infested inner cities, and so on and so forth. Trainers therefore must understand the social aspect of the curriculum. To a kid whose parents can hire bodyguards and one who lives in the slums with an abusive stepfather requires different approaches to methodology.