Survival by 120 hours is not required if:
1. The governing instrument contains language dealing explicitly with (i) simultaneous deaths or deaths in a common disaster and that language is operable under the facts of the case, (ii) deaths under circumstances where the order of death cannot be established by proof, or (iii) the marital deduction, or the governing instrument contains a provision to or for the benefit of the decedent’s spouse where it is the decedent’s intent, as manifested from the governing instrument or external evidence, that the decedent’s estate receive the benefit of the federal estate tax marital deduction;
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, including the death of another individual, for a specified period; but survival of the event, another individual, or the specified period shall be established by clear and convincing evidence;
3. The imposition of a 120-hour requirement of survival would cause a nonvested property interest or a power of appointment to be invalid under the Uniform Statutory Rule Against Perpetuities (§§ 55.1-124 through 55.1-129); but survival shall be established by clear and convincing evidence; 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; but survival shall be established by clear and convincing evidence.