Using the runCommand() method

usingRunCommandMethod.as

/* All the commands can be executing with the Document object. Simple
commands such as "getLastError" are run as below. The Document requires
a colon in all entries using shorthand, thus "getLastError:" */
mongo.db("myDatabase").runCommand(new Document("getLastError:")).addOnce(onLastError);

function onLastError(opReply:OpReply):void
{
    // The command response document will be in the first element
    // of the documents Array in the OpReply object. The structure
    // of the document will depend on the command executed.
    var document:Object = opReply.documents[0];
}