If a person opens a dishwasher, during a cycle, does the cycle start from the beginning?
No, when a dishwasher cycle is interrupted by someone opening it, everything resumes where it left off. If left open or off for too much in the middle of a cycle, several dishwashers may perhaps automatically empty or deactivate. However, some machines also don't immediately restart the cycle when the door is closed so you need to press start again.