Tap event not firing in Mobile Safari on an iPhone

Tap event not firing in Mobile Safari on an iPhone

Having real trouble trying to figure out what the heck is wrong with the
tap event for a vimeo handler. It works as it should on my desktop, but
when I try on my iPhone I get no response at all. Well, if I add the event
to body rather than the element I'm looking for it fires, but that's not
much help..
$(document).on('click tap', '.vimeo-play span', function(e){
alert('tap');
});

$('.vimeo-play span').on('click tap', function(event){
alert('tap?');
});

$('.vimeo-play').on('click tap', 'span', function(event){
alert('TAP!');
});

The actual code is run here.
Username: dev
Password: lolboy
And as you might guess it's the Play button that should be able to trigger
the tap event.