You said:
"Would a criminal even do this to a card for this price and wouldn't the grade contradict the card's appearance or be inauthentic if a criminal tampered with the PSA case? I HATE the idea of tampering and/or misrepresentation."
The short answer is YES. Unfortunately, I think you're about to get your card case back, cracked open, with a reprint in place of the card you sent to this guy. I hope I'm wrong, but let us know what you get back.