This test is made to determine whether a character acts fast enough when something rapid happens - such as a trap going off. A successful test indicates that the character has dodged, ducked, stepped back, or otherwise managed to avoid the sudden danger. Test against the character's I, making any suitable modifier for careless or gung-ho behaviour (e.g. -10% if moving at a standard rate, -20% if running, -10% if the character is showing off, etc.).