The MIIU is for minor injuries and illness which you cannot treat yourself or you think are unsuitable for a GP appointment. Following assessment, you may be advised to treat yourself, go to your pharmacist or see your GP if more appropriate.
If you are unsure always call NHS 111.
Out-of-hours services are generally busy so please think carefully before asking to see a doctor and only do so if you genuinely cannot wait until the surgery re-opens.
In a genuine emergency you should call 999. Chest pains and / or shortness of breath constitute an emergency.