I think that the bride only kills people once they're married and for financial purposes- and now that she's dead, there is no reason to do so.
However, I do have a solution to the problem of anything she says to you being heard be nearby buggies. Anybody remember that pinpoint sound idea that was talked about for the stretching room that would project sound so only one person would hear? What if, just as you turn away from the bride, that technology is used to make it seem like the bride is whispering in your ear. Maybe something like "Leaving so soon? Why, the wedding reception's just beginning!" and then maybe the axe noise.