As we have learned not just by reading but through experience, pre-hospital care is crucial because a lot could be addressed/a lot could escalate in the time where the patient is being brought to the hospital. Especially in accidents or trauma cases, proper management and emergency treatment done can make it or break it for the patient. In emergency medicine, we must think fast but also take into mind that we should not compromise the quality of pre-hospital care the patient receives.
Events starting from the onset are important to account since everything can affect the health outcomes of all patients. This is emphasized in EM because there is a small time frame to manage the patient as soon as possible. As stated in the question, other events are life-threatening, and every bit of management is going to be important to stabilize the patient before he/she reaches the hospital. With better initial management comes better prognosis if the patient reaches the hospital safely, and this represents a big chunk of emergency medicine. As physicians, we have to consider a lot of factors – especially social determinants which differ from area to area to be able to properly manage our patients.