Everything Went Dark

Jack quietly suggested that they call for help. Tatum fumbled for her phone and asked if calling 911 would be the right move. Jack took a step closer to Jennan and Evie and nodded. He had a small headache. He assumed it was from seeing his friends get sick and stop moving. As he got closer, the headache got more painful. He tried to ignore it. Tatum hadn't called for help yet. Jack looked back and tried to get her to call someone, but she stumbled back to the table and plopped down on the bench. She mumbled something about feeling really sick. Jack realized she wouldn't call anyone, but he can't use his phone. It had died on his way here. He noticed that Jennan's phone had fallen out of her pocket close to where he was.

How should he get help?