You oviously cannot, as the ending shows. I believe general Ross would hulk the fuck out about that.
I agree with you, of course they won't kill anyone but there's still some excitement lost in the plot for me when there's never any risk. Daredevil for this reason is more gripping imo.
i think the risk of the Avengers being broken up beyond repair is far more troubling than the risk of ... some random sidekick losing his life.
What people love about the Avengers, more than anything, are the 'buddy' moments. Those moments are at risk here!