That's really poor from EMR, putting you through all the time and effort for nothing. I would hope that they pull out all the stops and get you on a course in time, even it means them offering you a job at a different depot. I've read that it's not unusual to get a date a few days before you are due to expire - so don't give up hope.
At my stage 2 the assessor told us that there was nothing wrong in applying to other TOCs, but that we would probably have to resit the assessments. If you failed them, it would screw up your current application as the new result would in effect overwrite your current scores. Having said that, it sounds like you've not got anything to loose
I'm also sweating it out in the EMR Depot Driver talent pool, and starting to get a little worried that after all this there might not be a job at the end. Has anyone heard of candidates not being offered a position on a course after being the talent pool?
Hope they sort something out for you..