The 20th amendment states noon on Jan 20th ,, no way to get in before then and catch them before they issue pardons... although I would make it plain that if by issuing pardons the president expects to insulate himself against any future charges that it will in fact have the opposite effect.
Given the creative ways RATS have for reinterpreting the words written I'd say swearing in early still fits. It can be construed to mean that the 20th is only the final deadline to end power. If you go in early it still meets the criteria of having ended at least by Jan 20th.It would be be fun to throw the lefts creative antic of finding new ways to ignore the intent of something written into something else right back at them.