I forgot these were happening again. Tennants first run is a pretty good one, though upon rewatching this episode isn’t the best opener.

Thoughts for this episode:

• Within the episode plot, there’s some good stuff here. Lots of opportunity for angry doctor. It’s a good exploration of the ethics of the lab. It has to be vulnerable people who already have incurable diseases who help to test our new treatments. They’re effectively slaves in the episode but in the real world can you truly consent if you’re being offered something when you’re in a vulnerable position? Much less when being taken advantage of by for profit pharma companies funding the studies. The whole ethics thing might have been more impactful if we had seen a progression from something obviously harmless like single-cell brains or cultured meats (that we actually have right now), stepping slowly up to full life forms, as then there’s some ambiguity about where exactly you should draw the line.
• However, the actual logic of the entire hospital doesn’t make much sense if you think about it for more than a few seconds. The disinfection scene is amusing but it makes no sense. The solution of mixing a literal solution of different medicines feels like it can’t possibly work. Nor really did having lifts going to a basement people know nothing about - particularly a hospital that has hidden a whole load of secret stuff would surely have spotted it. And the footprint of the whole hidden lab seems bigger than the hospital itself.
• I am not a fan of the hospital set designs. The reception for the hospital looks like an airport check in desk. The wards don’t look much like hospital wards either. The CGI in the ladder and lift shafts during the “zombie chase” has not aged well at all.
• I wonder if they knew what they were doing with Bo at this point in the storyline. The idea of a silent watcher following humanity is a nice contrast compared to the doctor’s often quite obvious interventions. I don’t think it really meshes with who Bo ultimately is revealed to be, though. The general effects and his (their?) design are nice. The melody and themes used with the Bo meeting is really nice.
• As most of you already commented, the rose mind swap bit is quite awkward to watch, doesn’t really land for me. It’s good the doctor immediately clocks something is wrong, though he probably should have acted sooner. The swap isn’t much better in the doctor.
• The design and acting of the various cat nurses is really creepy and well done. Ditto the infectious pustules and scab effects, very offputting. The idea of a “petrification” disease is weird, but cool.
• The circular ending is a really nice way to round off the episode and humanise cassandra’s character - time travel used well here.

Two stand out lines this episode: “You’re talking out your arse” and “Who needs arms when you have claws”