The thing to remember is that while cute, koala's have a nasty temper and normally don't like humans. It just goes to show how desparate this little one was to just sit there and be touched. Also, they don't normally drink water (they get it from the leaves they eat) and this little girl drank three bottles of water!!
I've seen video of this as well, and you get the feeling that being able to help this little beast really gave a boost to the people fighting the fires. Moments after this was taken, they had to rush away to fight for someones house but Sam was picked up by wildlife carers and is now on the road to recovery.