Assembled assembly: Question for the Crafty

[LetItSnow]

Let's say that oh, hypothetically you're driving along, and you shift up a gear and the engine that you can see through your hood (you know, if you have one) pops a little up and to the right, and when you get home, you notice that there are no bolts in the driver's side engine mount going to the block like there are supposed to be.

Not that that's happened to anybody.

Is it possible to replace that rear bolt without removing (or even lifting!) the engine?

I'm sure the answer to this puzzle will come in handy for someone someday. You know, if this ever happens.