SM
Bigfooty Legend
See the above discussion with bourbons. Apparently it wasn't in the game so it might not feature in the show.
At some point Riley would 'turn' and attack Ellie. Ellie's self-preservation instincts would kick in and after a struggle she kills Riley. Then she is faced with the huge question of what to do next. She believes she's infected so would be inclined to kill herself, like the option 1 they talked about. There's even greater motivation for her to do that than Henry after he kills his son, Sam. But we know she doesn't. Maybe they could fudge it by having Ellie knocked unconscious for long enough for her to realise her infection wasn't spreading.
You'd think she's distraught from killing her friend and passes out from drinking, wakes up still unconverted and figures it out.