Depends on how far away your wife's friend is for one, but there could be many possible outcomes. Distraction/diversion, whether the dog is in one room or not, who else is in the house, how the dog reacts to you...
She`s obviously not much of a friend not to meet you, but leave her savage dog in your house with your seven cats, budgie, your 95 year old grandad ( who`s only got one leg, and is permanently needing the loo) and your irreplaceable collection of ming vases. What a cow.