No one ever just says Peter when they say Peter Lukas, I’ve noticed. It feels weird to say Peter. I mean, you can even get away with saying Gertrude or Jonah or Simon, other common characters that I see both names used for a lot. But no one says Peter.

Saying both a first and last name for him distances him from us a bit. Makes it more formal and detached. Which is perfect for a Lonely avatar.

Edit: going through the statement transcripts, in the beginning of the show he is called Peter Lukas far more often. He even introduces himself as Peter Lukas once. But! Then! We have many, many more instances of just Peter, mostly by Martin. Peter even tells Martin to call him Peter. Elias also calls him Peter, as does Jon a few times. Simon calls him Peter a bunch of times, I suppose from familliarity (like with Elias).

So if we take Peter Lukas vs. Peter it’s 14-63 roughly. However, if we take out mentions by Martin, Simon, or Elias, it’s 14 to roughly 12. And, again, Season 4 is where we get almost all the Peter’s and almost no Peter Lukas’s.