Had a quick look at the code, I've only done an Erynn run so I'm guessing, but if someone can put 2 and 2 together
This image triggers when at the training camp, with the flag Erynn_Week3_Wednesday_Lying == True. Looking for that variable, I'm guessing it occurs if you don't break things off with Alexis for Erynn, and then when making out with Erynn and she doesn't want to take it further, you go to Alexis instead, and when Erynn confronts you, you accuse her of lying. This ends both Erynn and Alexis' path.
Like i said, i haven't actually done any other path other than solo Erynn, so i can't say for certain.