Self-Destruct is Irrational Component

[dmm]

If someone Boards a ship with self-destruct (SD), then the SD destroys both ships. Even if the boardee is an escort and the boarder is a mother ship!

So, if SDs are so powerful, why can't a ship that is clearly doomed move up next to an enemy ship and initiate the SD, thereby taking out the hated enemy? (Or at least doing a heck of a lot of damage.) After all, you can commit noble suicide by ramming, and you can even plan for it with explosive warheads.

A rational SD should only be powerful enough to destroy the ship that carries it. Collateral damage should occur to ALL other ships next to it, and should be rated according to the size of the ship with the SD.