This particular user sayeth thus:
Dropping out the audio for a frame will work nicely with keyframes on the levels effect, just by setting two on either side at normal levels, and modifying the middle one to zero or -48.... whatever it is. Use hold keyframes. But I think it would be easier to do in a video editing application, frankly...
Video dropouts: how real do you need them to look? Case in point: with inteerlaced video, you can get a dropout on a single field. I've seen & fixed enough of them to know it's true.
Forgive me if I'm misunderstanding, but if you just want the video and audio to cut out without any fade then using hold keyframes as Dave suggested should work.
But, if you would like to fade them both out then you can use normal or eased keyframes with a bigger seperation between the two keyframes on either end of the drop out.
Thanks for the input, guys. Much appreciated.