Surprises in Luke- Daily Reading, Luke 9

This chapter feels sobre (v5, v21-27, v41, v44, v52, v57-62) as we see the cost of following Jesus as he 'resolutely set out for Jerusalem' (v51): how do we live out v57-62? And there's lots of surprises. Without a portable PA, how did Jesus speak to such large crowds (v11, v14)? Why such a strict warning in v21 and were the 3 disciples meant to be silent in v36?  Why an almost humorous picture of Peter in v32-33? Why was understanding hidden from the disciples in v45? Could the disciples have called down fire from heaven in v54? http://www.biblegateway.com/passage/?search=luke9&version=NIV