So I noticed something in the new episode, and finally decided to make a theory about it.
(POF - SVSR at 3:16)
Patton has the blue eye w/ flame thing Sans (from the game Undertale) also has (the flame is fanon and not canon, but is still highly associated with Sans)
Time to theorise the shit out of this.
Okay, so Sans and Patton are two very different characters. Except for making puns, I didn’t get why Thomas would make the connection between Patton and Sans at first. but. I think this is to make a link between Patton and the main theme of Undertale: DETERMINATION.
In this scene patton says “But in your face I saw this pain and so-“ before getting cut off by Thomas. At the end of the video he says “Like I told you before: sometimes I don’t know the way. But when I told you that.. you were so scared. I couldn’t bear it. So I said to myself ‘Alright Patton, Thomas needs you. You’re responsible for his morality. You can never not have an answer for him.’ And then I promised you I’d keep fighting.” That sound pretty damn determined to me.
‘But why would Thomas choose Sans? And why the eye?’ At first I tried to analyse the scene in Undertale where Sans has the blue eye / uses his powers: the judgement hall. (For people who don’t know Undertale: the judgement hall scene is where Sans confronts Frisk about their actions throughout the game. If you do the genocide route (kill everyone you come across) you will have to face Sans in a boss battle. He uses his powers here, causing his eye to turn blue, just like Patton’s eye in this scene.) But I couldn’t find a single reason for Thomas to choose it (lemme know if you do find something), except just because it was the easiest way. The connection to DETERMINATION might have been stronger if Thomas had chosen Frisk or Chara, but simply making Patton’s eyes horizontal lines (like Frisk) or red (like Chara) probably wouldn’t have gotten the point across. The other option would have been changing Patton’s entire outfit to Frisk’s or Chara’s, but that would’ve been to obvious. By using Sans, and particularly the judgement hall scene where DETERMINATION is very much present, Thomas made a simple and easily recognisable link.
TL;DR: I think Thomas used the connection between Patton and Sans to show that Patton is very determined to do the right thing.