You can use the FQL table event_member to query for
https://developers.facebook.com/docs/reference/fql/event_member/
An FQl query for you event is
https://graph.facebook.com/fql?q=select+uid,+rsvp_status+from+event_member+where+eid=599978450080176&access_token={ACCESS_TOKEN}
You can use it via the JS SDK like this:
FB.api('https://graph.facebook.com/fql?q=select+uid,+rsvp_status+from+event_member+where+eid=599978450080176&access_token=' + access_token');
What you can't do without having the User's user_checkins permission is to crawl for everybody who checked in you Event, which you'd need to gather via an App.