IMHO, The Lazarus Effect was possibly the tightest script of series 3 so far. It wasn't particularly innovative, but it was a solid mad-scientist-turns-into-monster yarn. I also liked how Martha's family seems to be splitting, and I wonder how Tish will fare with no Lazarus at the head of Lazarus labs, but with funding from Saxon likely to continue...

The remainder-of-series trailer blew me away - they really know how to cut those together for edge-of-the-seat effect. Saxon in an oxygen mask rapping on the table at Number 10 at the end stole the trailer, IMHO, with no dialog.