[moe]

Otherwise a webpage has to escape its own sandbox, bypass the native client's sandbox (in a different process) composed of the inner and outer sandbox and then access the native client.

Or there could be just some really dumb bug that somehow enables cross-process access. With javascript. You know, one of these silly brown-paper-bag bugs that are not supposed to happen.

Either way, this is the second door. It may be a shiny steel door, but it's an additional door.

[BitMastro]

The other process might as well be ssh itself at this point. Anyway, we are just speculating, also the wall is another door if you smash through it. Just don't use it then.