Sharing Studio Space

If two mix engineers had to share the same studio space (one doing audio, the other doing audio and video). What would be the best thing to do to keep from interfering with each other's recordings? Obviously, space is an issue, or I wouldn't be asking this. I know the obvious solution would be "mix at different times" but that really isn't an option in this case.

Put a an acoustic separation and mix at low volumes or simply mix using headphones.

Headphones.