I don’t think it was “loaded”. She pulled back the string and the arrow, but I don’t think the arrow was actually nocked at that point, making it completely safe. There’s guide that’s holding the arrow in place, and keeps it from dropping out as she moves to aim it at the target. Up until this point, the arrow has not been nocked. You then see her push the arrow forward, so that the nock is past the string. Then she pulls the arrow back, nocking it, and then shooting it. If the arrow had been nocked up to that point, there would be no need to have pushed it forward.
So, while it was perfectly safe, it nevertheless made Simon wet his pants.
