That was actually the good ending. It even says during the ride that if it had to choose a place to die, that would be it.
If you wait too long the Holiday ends, and your bitBuddy thinks maybe the code will reset in 24 hours. As you wait the bitBuddy slowly turns grey, it will occasionally greet you if you move the mouse, and at 24 hours it will say "The Holiday promo didn't reset, did it? I knew it wouldn't. I just wanted to think it would."
The bitBuddy's natural lifespan appears to be 1 week real world days, which are paused when the computer is put into hibernate.