When you commit a crime, such as burglary or purse snatching or mugging, you are leaving yourself open to misinterpretation of your intent. Yes we all know that you are just this harmless little product of a deprived childhood, who needs money for your drug habit, and you wouldn't dream of hurting anyone who doesn't resist your demands for money, but the victim may not be aware of your good intentions, and may misinterpret your breaking into his home as an attack.
In other words, you are taking your life into your own hands when you commit robbery, burglary or other potentially violent crimes. Maybe you believed the house was unoccupied, (seems unlikely in this case) but the home owner doesn't know that, especially when he is an 82 year old man, who would be extremely vulnerable to a physical attack.
