This attitude could go a long way in explaining why it is that Doc doesn’t berate Marty about the blown amplifier when they meet up later that night at the Twin Pines Mall to run tests for the DeLorean Time Machine. However, there is another funny possibility to consider, and one that I offered to Gale: it’s possible that Doc never actually saw the destruction. He was clearly busy on the day in question preparing for his big experiment, and while he must have ducked home at some point just to get the plutonium in the case under his bed, it wouldn’t be out of character if he was so excited about his big night that he didn’t even notice that his home had been destroyed.