The term 'Sudden Flow From Outside' can be summarized as an 'INRUSH, ' which is a six-letter word. An INRUSH is a sudden, large influx of something from outside, such as water, electricity, or air. It is often used to describe the sudden flow of a large amount of liquid or gas into a system or container. In electrical engineering, an INRUSH is the initial surge of current when a switch is turned on. In plumbing, an INRUSH is the sudden flow of water from a pipe or other source.