Ambulances take time to arrive and sometimes people retreat back to bedrooms because they feel safer there. Even if you feel awful however unlocking the door is essential because medical staff must be able to get inside in order to help! My wife suffers from acute allergies (requiring Epi-pens). When she has had to use one whilst at home alone she phones 999 and then ensures the door is unlocked just in case she collapses before help arrives.