walt stepped up and didn't let kingpin gus kill jesse.
jesse got high and was ready to get into a gun battle with the 2 dealers (who killed the little dealer kid on bike to tie up loose ends) when Walt pulled up and ran them both over.
One tried to get up, so Walt picked up his gun and shot his brains all over the sidewalk. He looked up at jesse and said "Run".
Heisenberg is back. Season finale next week looks cool!