When Prairie makes a sandwich for Hap, the mustard has a lid on it. A few frames later, the lid is totally removed. Prairie reaches for a plate and when she turns around, the lid is again on the mustard bottle.
An injection of epinephrine only lasts for about 15-20 minutes. After that the epinephrine would wear off and if the allergen was still in your system you would start to go back into anaphylaxis. As the doctor is allergic to tomatoes, he would continue to go into anaphylaxis as long as he had tomatoes in his stomach. A single injection of epinephrine wouldn't have solved that. As he never went to an ER and had his stomach pumped and only had the one EpiPen, he should have died.