Overriding the Backbone.js comparator

I have a simple backbone.js twitter application that should sort the tweets in reverse order. I am currently using a date sorter. When the Reverse button is pressed (as seen in the view), how can I change the sort order of all tweets without returning through the comparator? My impression is that when I call the sort, it will try to re-display the list (this means that the comparator will sort the data again, which is undesirable). How do I override this?

Tweet = Backbone.Model.extend();

 // Define the collection
Tweets = Backbone.Collection.extend(
{
    model: Tweet,
    // Url to request when fetch() is called
    url: 'http://search.twitter.com/search.json?q=codinghorror',

    parse: function(response) {

        //modify dates to be more readable
        $.each(response.results, function(i,val) {
            val.created_at = val.created_at.slice(0, val.created_at.length - 6);
          });

        return response.results;
    },
    // Overwrite the sync method to pass over the Same Origin Policy
    sync: function(method, model, options) {
        var that = this;
            var params = _.extend({
                type: 'GET',
                dataType: 'jsonp',
                url: that.url,
                processData: true
            }, options);

        return $.ajax(params);
    },
    comparator: function(activity){

        var date = new Date(activity.get('created_at'));
        return -date.getTime();

    }
});

   // Define the View
  TweetsView = Backbone.View.extend({
initialize: function() {
  _.bindAll(this, 'render');
  // create a collection
  this.collection = new Tweets;
  // Fetch the collection and call render() method
  var that = this;
  this.collection.fetch({
    success: function (s) {
        console.log("fetched", s);
        that.render();
    }
  });
},

el: $('#tweetContainer'),
// Use an external template

template: _.template($('#tweettemplate').html()),

render: function() {
    // Fill the html with the template and the collection
    $(this.el).html(this.template({ tweets: this.collection.toJSON() }));
},

events : {
    'click .refresh' : 'refresh',
    **'click .reverse' : 'reverse'**
},

refresh : function() {

 this.collection.fetch();
console.log('refresh', this.collection);
 this.render();

},

**reverse : function() {**

    console.log("you clicked reverse");

    console.log(this.collection, "collection");

    this.collection.sort();

   //How do I reverse the list without going through the comparator?

**}**

});

var app = new TweetsView();
 });