[DangitBobby]

I would also consider this to be memory unsafe. If you have an "array", you should not be able to index (or slice) beyond its bounds. If you are allowed to do so, you may have unpredictable junk in your array.

[morelisp]

This is not any usual definition of memory-unsafety; the contents may be useless to your task at hand but it's well-defined.