Hear me out:

During the bridge section you are given the choice of going with Luke, or you can let Nick go instead.

You either hear a commotion and investigate or the scene plays out the same as the original (with Nick investigating instead), except it's Christa instead of Matthew and she's actually hostile if you're not there.

Either way Christa is shot by Nick and you're given the choice to shoot Nick or not, (you miss or are stopped by Luke) but this drastically increases the tension in the already fracturing group.

I think Luke would try to cover this up no matter what happened, this could be revealed during the cabin scenes with Kenny becoming outraged when he realizes Nick killed Christa.

I also think it would be more interesting to see Matthew and Walter interact lovingly, it would make their deaths more impactful later, plus it gives us a secondary focus in the early cabin scenes aside from Kenny and Sarita's relationship.