Ok. I just saw a promo for "After Hours" on Global, in Canada. In previous promos, it has been exactly the same as the FOX promo, but this one ended slightly differently.
In the scene where Cuddy walks in on House in the bathtub (at least it looks like it was at that moment--it may have been edited--it may have been while he had her on the phone if he was using speakerphone), he says to her "I tried calling everyone else"
Not much, but it does answer the question as to why he called Cuddy...and it makes sense seeing as the others all seem pretty busy as well!