What is the sum of 0x0000002 and 0x0000003 ?
The bit patterns for these small integers are easy to figure out. You may have to use the slider on the register display to see register ten.
If you push F10 again, the PC will point at a word in memory that contains bits not intended to be a machine instruction. However the simulator will try to execute those bits. A real processor would "crash" at this point. (This is sometimes called "falling off the end of a program"). The simulator prints an error message in the bottom panel.
What happens in real computers when the end of a program is reached?