On Unintended Consequences

That is how Geass works. Its side effects.

One sunny afternoon it just gets out of control and cannot be deactivated by normal means anymore. When that would happen is completely unpredictable. So just a minute ago you chat idly and feel chill about it all and the next moment it just fires off and you get the results you did not wanted to see.

In fact Code Geass does well to illustrate that your actions often have the unintended consequences you cannot predict even if you are super genius like Lelouch.

It is same how Shirley's dad was killed. He was just another unnamed casualty of war who probably piloted one of the knightmares that were caught in the avalanche. Lelouch sure did not intended for him to die and he surely did not want to make Shirley sad, but it did happen. That is just how world works.

Yet despite that one still want to blame someone for the misfortunes that befell on them. Mao exploited that and convinced Shirley to shoot Lelouch.

That of course is not a universal rule and some other people in turn do bad things intentionally and then try to blame it on something else.

However, Lelouch more often than not suffers from unintended consequences of his actions.