See, I would have just told her. A quick "Lois, the important thing I had to tell you is that I'm Superman and I have to go right now to rescue a derailed train," would have done just fine. That way he's kept his promised to tell her the important thing, and he's provided a reason for his quick departure. Honesty and keeping promises are always a good idea. Mind you, "I love you," is pretty honest, too.
BTW, I have no idea who Vanna White is, so the comparison meant nothing to me. It's worth considering whether you want to include references like this, knowing that they'll always be meaningless to at least part of your audience. Better, sometimes, to use more generic descriptions.
Yvonne
