Luke shouldn't know anything about his father being killed at the moment because that scene happened [u]outside[/u] the Manor.

I think the bombs on the roof should go off. I mean, why plant them if you're not gonna use them? =P
Besides, he didn't cover the [i]entire[/i] roof with bombs so the Manor shouldn't be totally destroyed. The question would be, will the Tandem be able to escape before/afterwards? Or are they captured?

And, where are Kate & Steph?