We had spent part of the afternoon/evening reviewing material from my most recent flight lesson, and over dinner, I had been getting my husband to quiz me on various emergency procedures. My kids were quite interested, and asked all kinds of questions. I basically told them I was practising thinking about "just in case" scenarios.
I guess Alex decided to consider some of his own "emergency procedures". (BTW, I suggested that in the unlikely event of a robber appearing, he just run.)