A pregnant woman with severe nausea doesn't want to take any anti-nausea medication because her OBGYN told her those type of drugs would be harmful to the fetus. While this is true for certain nausea medications, there is one commonly used to treat pregnancy related nausea called ondansetron (Zofran), and any type of nausea. Ondansetron was developed to be a more effective alternative to other nausea medications without undesired side effects, as most nausea medications prior to the release of ondansetron caused drowsiness. Several studies showed that ondansetron is not only more effective at treating pregnancy related nausea but also showed no ill effects on fetal development. Ondansetron is also very effective in treating nausea related to cancer and chemotherapy, gastroenteritis, irritable bowel syndrome and opioid induced nausea. It tends to have side effects less commonly than other nausea medications, but can cause headache, diarrhea, constipation, itching and drowsiness.
When Peter backs into the pedestrian after filling Elizabeth's car with gas you can clearly see that there is a car directly behind him. He would have reason for going in reverse.