from the article:

Writing to random locations in system memory isn't generally a wise design practice. Unsurprisingly, the game would generate spectacular crashes as a result. A human player would be driving blind and usually crash right away, limiting the scope of system casualties. The AI opponents had no such weakness. The computer would scan immediately in front, to the left, and to the right of its position to determine if it was about to hit a wall and change directions accordingly. So as far as the computer was concerned, system memory looked no different than screen memory. As Marco described it,

We can only speculate what it started doing once it left screen memory, since it obviously would look to find a way to continue going in a direction that was occupied by 0’s. If it became blocked and ran into a “wall” of numbers, it would die. In those spectacular crashes though, it would sometimes be running around very much “alive” until at some point it either overwrote some code being executed with a trail that didn’t make sense, or it would access some memory mapped device that would then cause a crash. But it wasn’t immediate – the AI ran around for a little while out there before it crashed the system.

-- Wow, thanks for this - the imagery here is great.