[{name:"A",value:1},{name:"B",value:2},{name:"C",value:3}]

db.collection.aggregate([{"$facet":{"q1":[{"$match":{name:"B"}},{"$limit":1}],"q2":[{"$match":{value:3}},{"$limit":1}],"q3":[{"$match":{$or:[{name:"B"},{"name":"C"}]}},{"$limit":1}]}},{"$project":{tempField:["$q1","$q2","$q3"]}},{"$unwind":"$tempField"},{"$unwind":"$tempField"},{"$replaceRoot":{"newRoot":"$tempField"}}])