So, I had a thought...
[not a likely one, but its devious and something I'd do, if I were Pence.....]
So, using article 25 does not remove the ability for Twitler to try and pardon himself, or even ask for a pardon. And it definitely does not keep him from ever holding office.
Only an impeachment keeps him from being pardoned ever, and from ever holding office.
Right now, I'd lay odds that Romney would remain firmly a yes to impeach - negating Pence from having to tiebreak. I'd also half expect a few of the cagier republicans to maybe do the same. [Hell, if i were a republican in congress or the senate, I'd be ready to excise the cancer from my body and rebuild].
Anyway, obviously, I'm not any of these things - if I were, I'd have article 5.4 on the 21 of jan 2017, or voted to impeach the first time around.