[tangue]

I don't know about the internals of the chess engine you are talking about but it would be interesting to read about it.

Basically most engines are minimax (or proof-number search) and alpha-beta pruning based. I guess that in the game you describe the algorithms are the same but it choses the worst scores instead of the best ones. It's commonly called "suicide chess" and when two suicide-chess AI confronts, there are always strange results.