Intercalating shouldn't be seen purely as a way to 'improve your CV' to help you get into competitive jobs. There is absolutely still a point in intercalating if you're wanting to do emergency medicine and the fact that there's low competition for jobs shouldn't mean you aim for the absolute minimum just to scrape in. There is a benefit to doing extra study that is beyond the extra post-nomials. If you're interested in the subject and want to go into that as a career, you'll be learning specific things that are useful day-to-day as well as gaining loads of extra skills that you just don't really get a chance to develop during the pure MBBS (research, presentation, leadership, literature review, process of research, etc). You're going to be a much more attractive candidate with extra qualifications, which means you can be more selective in picking your jobs. Also don't forget that your degree is for life, and will also "count" when applying for consultant jobs.
If you are wanting to do extra study at some point in your life, it makes a lot more sense to do it now. Yes, you lose a year of your life but 1) your tuition fees are paid for (whereas if you do it at any other point you're gonna have to fork it out yourself) and 2) you are still in the student mind-set, where it is not going to be difficult to study.