OK, so it's obvious HANK caught on from what we can see at the end of the last episode. Think back a couple episodes when WALT called MIKE and warned him that the cops were coming for him while he was at the park with grandchild....WALT just loves to place warning calls now doesn't he?
You may also remember how HANK was warned right before the brothers were coming to slay him in the DEA parking lot... ""2 MEN ARE COMING TO KILL YOU IN 1 MINUTE."" yeah, there was a voice changer but come on, it had to be WALT that warned him.... So, to sum it up, HANK owes WALT his life wouldn't you say??????!!!!????