Can you explain?

Two persons are travelling in a car at the rate of 45 kmph and suddenly the person driving the car stops in front of a shop to buy some items and after purchasing the same, reaches the car when, to his surprise and dismay find the other person dead and moreover a stranger is inside the car. The stranger had not entered the car before they started nor the second person who was dead let him in while the first one went to the shop. What is the possible and logically correct explanation you can give?

Answer:

The two person were a man and his wife, and the lady was on labour and so they were rushing to a hospital enroute a shop to purchase some pills and the woman delivered a child and herself passed away in the post-delivery complications.