While the issue discussed here is very serious, and some poor sod lost his life, the issue it indicates is even more so.
If you can clamber into the gear it's even easier to rig a bomb and throw it in there. I won't be silly enough to detail the simple electronics even a dunce like me could put together.
It's bad enough that one bloke died. A 757 or greater falling onto a major conurbation like London is on another page.