I don’t think he expected that. It’s pretty clear that he expected to be able to pause/debug a script, at the same time as he’d be able to move around in the editor viewport, and inspect object properties in the editor viewport.
This is not an unreasonable expectation, as a user.
But, Unreal doesn’t support it, and there are some pretty deep reasons why it doesn’t, currently, support that.
Meanwhile, whether the editor runs all, partially, or not at all in the Blueprint VM doesn’t really matter. (In fact, it may do all of these things – are you running any editor widget blueprints? That certainly runs in the blueprint system itself!)
It might be possible to support some kind of “detaching” of the object being currently break-pointed, so that the rest of the scene can keep running, but there are many, many, ways that this could “go wrong” or lead to the debugger not being able to debug actual problems, because “stop the world” is the only way to be sure that the debugger works on the state that the game actually sees.
Which is not particularly helpful when you’re stopped at a breakpoint and want to check the state of other objects.