[{"desc":"sub 1","patterns":[{"pattern":"^R"},{"pattern":"^S"}]},{"desc":"sub 2","patterns":[{"pattern":"^L"},{"pattern":"^M"}]}]

db.collection.find({"$expr":{"$anyElementTrue":{"$map":{"input":"$patterns.pattern","in":{"$regexMatch":{"input":"Room1","regex":"$$this","options":"i"}}}}}})