I hate it when they write themselves in to corner and use some Deus Ex Machina to get themselves out.
It was seeded throughout the episode. It's not a deus ex machina.
It doesn't make any less of device. That we have seen again and again.
The more I reflect back on this, the more disappointing it is. All of the stuff with Clara, the advancement of their relationship, wiped out. The next few episodes could've been so much more potentially interesting with Clara mistrusting the Doctor, and perhaps having her OWN mystery to unravel... But, no. Blank cheerful Clara... again.
She's slowly becoming an uncharacter. She's cute and bubbly enough to keep fanboys interested and in their beds at night, but she's more of a MacGuffin than an actual flesh and blood character with depth, needs, goals, etc.
Personally, I don't really care about her, or her "impossibility".... in a Universe like Doctor Who there could be a million reasons why she has existed... he travels in a fucking TIME machine... why is she SO impossible?
Bleh. This series aint so good.