Originally Posted by Jazbaa1:
“The drink driving is very wrong and fair enough if someone has a go at her about that but that's got nothing to do with certain characters acting like she killed Maddie and Kal. Deliberately.”
They are quite similar though in respect that she decides to drink which impairs her senses leading to danger for others.
The scenario, as everybody until Tracy's confession understands it, is that Carla drank so much that she was not capable of deeping her flat safe, ie lighting and leaving a candle. Lighting a candle can be dangerous, it shouldn't be done and left due to the danger of it causing something else to catch fire and by drinking so much that she passed out she was irresponsible and that irresponsibility caused deaths.