[{"_id":5,data:{"quizzes":[{"wk":1,"score":10},{"wk":2,"score":8},{"wk":3,"score":5},{"wk":4,"score":6}]}}]

db.collection.update({_id:5,"data.quizzes.wk":{$ne:5}},{$push:{"data.quizzes":{wk:5,score:55555}}})