Of course, the Nintendo cartidge was ruined before the Apple IIgs, giving the lie to any claims of simultaneity. In fact, it would appear to be impossible to ruin two pieces of (computer) hardware simultaneously. Not for the usual reasons of special relativity (after all, we may assume the 2 pieces are in the same position and reference frame), but rather for reasons having to do with electronics. Once the first starts giving out smoke, usually no current will flow through the other. However, JoeBaldwin kindly point out that with your computer hooked up to the phone line via a modem, a single bolt of lightning can ruin both the modem and the computer! But... Is a modem card a separate piece of equipment? Are computers hooked up to separate modem boxes also vulnerable to this? Just in case, he suggests employing an EMP.

Another counterexample might come from HiFi, where it's probably possible to ruin your amplifier simultaneously with something else (ruined amplifiers are supposed to be able to supply voltage to other gear...).