Any employee who uses Gmail personally has two accounts, yes (I actually have four - personal, .edu, my pre-Google startup, and Google). No one outside the corp environment can see my corp account. From my corp account, I can't find my personal account by searching. If I go directly to my personal profile page and try to circle my personal account from my corp account, I get an error "due to domain restriction".

So I guess the short version is no, what you are concerned about won't happen.