Facts, fictions, Noah's non-violence

I have to admit, I don't know what to say sometimes when people are starting from a very different place. I'm particularly thinking of church Bible Study groups where the dominant view is very much that it all happened - and although one member seems to feel free to state their scepticism, it very much feels as though I, as the minister present, would not be so free! After all, I represent "what the church believes", it is assumed. So even though our recent group seemed happy enough with evolution (thankfully!), they still wanted my inclusive statement ("We can believe in evolution and take the Bible seriously") to mean one thing: "yes, it all happened, even if in slightly different ways."
I am, though, a coward! So even though it was possible to get a wedge into the gap when we were talking about Noah - by suggesting that the story reflects a people's way of "making sense" of a large, localised flood in the community's memory, rather than representing God's "will" as such - I still stepped back from saying "and so the 'facts' of this story simply are not crucial." Even so, we did get to the interesting point ... that the symbol of God's covenant is a 'bow', a weapon of war, reminding us that what had angered God to act so decisively had been humanity's utter violence and self-destructiveness (see Genesis chapter 6: 1-8). The symbol, not simply a beautiful rain-bow, is double-edged ('literally'!): for it reminds us of the violence, and then the cost of violence - the rain which flooded the destructive people. So Noah's family stands as a haven of non-violence ... and this beautiful symbol reminds us of that dream. Not so much the fairy-tale for children of cute animals on an ark, but a poignant judgment on humanity's inhumanity and violence ... why won't it stop?