@cervi_fae_ Also, if I remember correctly, Fizz talked about this series of murders earlier in the episode pretty nonchalantly, so I think learn that he's basically the one killing these people really got to him
@cervi_fae_ Could be because Fizz himself isn't a killer, so seeing a twisted version of himself killing people is probably messing him up (I don't actually remember if he has killed anyone or not, it's been a while since I've watch the earlier seasons)