When bringing the paralyzed victim to the hospital, a station wagon style ambulance is shown pulling up to the hospital. When the patient is unloaded, the ambulance is a box-style ambulance.
When in the ambulance checking the baby's heart beat, the stethoscope is being used upside down.
Some stethoscopes are double-sided, one side is the diaphragm and the other is called the bell. Due to its size the smaller head is more accurate for a focusing on a particular area for a sound such as a fetal heart sound.
The man being rescued from under the boat has a severed artery which Johnny has to hold to attempt to prevent him from bleeding out. When he is pulled out there is little or no blood, down the victim's arm or on Johnny's hands.