Final answer:
Administer the epinephrine auto-injector to counteract the allergic reaction's effects, provide high-flow oxygen, and seek medical control assistance.
Step-by-step explanation:
When facing a situation where a person is experiencing a severe allergic reaction and you don't have a cell phone signal, you should administer the epinephrine auto-injector. The epinephrine injection helps to counteract the drop in blood pressure and alleviate breathing difficulties associated with anaphylaxis. While waiting for medical control, it is important for your partner to provide high-flow oxygen to the patient.