This subchapter does not apply if:
(1) the governing instrument contains language dealing explicitly with simultaneous deaths or deaths in a common disaster and that language is operable under the facts of the case;
(2) the governing instrument expressly indicates that an individual is not required to survive an event, including the death of another individual, by any specified period or expressly requires the individual to survive the event for a specified period;
(3) the imposition of 120-hour requirement of survival would cause a nonvested property interest or a power of appointment to be invalid under any rule against perpetuities; or
(4) the application of a 120-hour requirement of survival to multiple governing instruments would result in an unintended failure or duplication of a disposition.