I think that it's because that they would meet Pongo for some reason.  Why else would Pongo be there?  It seems that everything the author has put in the story has some purpose.  Jack souped up the "53" so that everybody knows that Jack is a mechanic.  Isadora comes in the story to help Jack out because Grady obviously, isn't being much help that.  That we know of at least.  Jack needed to have someone who had the same mind-set as him so he could have help in the situation that's going on.