How about, then .. if he was always so worried about that situation arising .. that he made sure he set his alarm system, that he made sure the bathroom window was *locked*, that he made sure the ladders were secure, that he made sure the balcony doors were shut at night, that he made sure his aircon was working?
.. and yet he didn't do any of those things? That tells me that he actually was never really that worried about the security of his house, and that he wouldn't have suddenly, and mistakenly, suspected someone was climbing through the bathroom window and go on red alert (his text about the washing machine was just him joking around .. it probably made him jump, like things sometimes do, and he decided to make a bit of a joke of it to his mates via twitter). He was never that worried about being broken into .. he couldn't have been to have been so lax with his security .. so why, all of a sudden, is he now so worried that the minute he hears a tiny noise (and seeing as his girlfriend is stopping over, is more than likely going to be her) he thinks it's an intruder and goes on a shooting spree?