Parallel execution in node.js - Step package

I get confused when look at code supposed to be return in random order.

However, this parallel code will be executed in an ordered way ?

How come will this be?

Here is the snippet comes from Step library.

require('./helper');

var selfText = fs.readFileSync(__filename, 'utf8'),
    etcText = fs.readFileSync('PureString', 'utf8');//encoding option is specified then his function returns a string

expect('one');
expect('two');
Step(
  // Loads two files in parallel
  function loadStuff() {
      fulfill('one');
      fs.readFile(__filename, 'utf-8', this.parallel());
      fs.readFile("PureString", 'utf-8', this.parallel());
  },
  // Show the result when done
  function showStuff(err, code, users) {
    fulfill('two');
    if (err) throw err;
    assert.equal(selfText, code, "Code should come first");
    assert.equal(etcText, users, "Users should come second");
  }
);