To understand this one you probably need to know something about the Area 51 and Roswell incident. But I guess there aren't that many people left who have never heard of it after all the mentions in films, TV, books,...|
But well, a change of your appearance can also be an alienation in every aspect of this person called "you". And if you're no longer yourself, you can be mistaken for someone else, which can have other inconcenvient consequences. Besides the fact of having committed murder on your older self of course. Seeing it this way, this strip even includes already in the first panel a successful suicide attempt.
And just as a side note: Even if you can't see yourself anymore, don't remove the rear- and side-view mirror from your car.