[{_id:1,"exercises":[{id:1,parameters:[{values:[1],_id:1},{values:[2],_id:2},{values:[3],_id:3},{values:[4],_id:4},{values:[5],_id:5}]}]}]

db.collection.update({"_id":1},{"$unset":{"exercises.$[].parameters.2.values":"","exercises.$[].parameters.3.values":"","exercises.$[].parameters.4.values":"","exercises.$[].parameters.5.values":""}},{"multi":true})