Hank finally put two and two together at the end of the previous episode, which in one sense means that Walt's luck had run out. But we're dealing with Walter White, here - Walter, who, as we've seen, makes his own luck.
So the confrontation between Hank and Walt at the end of tonight's episode was all that we could expect and hope for. Walt is out-matched, physically, by Hank, even though Hank has not completely recovered from his near-paralysis. Walt absorbs physically punishment meted out by Hank - a punch to the face that knocks Walt down. But Walt, by sheer power of his intellect, comes out on top of Hank at the end.
In classic Walt fashion, he uses his cancer to dissolve at least a little of Hank's resolve. Walt may well be lying. You can never can tell with Walt. We also see in this episode that Walt lies point blank to Jesse about not killing Mike - we saw Walt shoot Mike in the car with our own eyes. But he lies so well that we can almost doubt what we saw.
But, even more importantly, whether Walt is now lying about his cancer recurring or not - we do see him getting what looks like chemo therapy, so probably he's not lying - doesn't really matter. Because the point about Walt is he'll do whatever it takes. Lie about this cancer or be truthful about it - whatever will do the job. And that's what makes Walt such an appealing character.
In the brief flash-forward at the beginning, we do see that something game-changing happened between now and then. Are we seeing Walt on his way to checking out? My money is on not - I'm betting Walter's will to live and triumph will trump everything.
Whatever happens, we're clearly in for one ultimately getting-down-to-business hell of a ride.
See also Breaking Bad Season 5 Premiere: Riveting Entropy ... Breaking Bad 5.3: Deal with the Devil ... Breaking Bad 5.7: Exit Mike ... Breaking Bad Final Half-Season Finale
And see also My Prediction about Breaking Bad ... Breaking Bad Season 4 Debuts ... Breaking Bad 4.2: Gun and Question ... Breaking Bad 4.11: Tightening Vice ... Breaking Bad 4.12: King vs. King ... Breaking Bad Season 4 Finale: Deceptive Flowers