Superman was trying to drive the thing back so that he could keep as many people alive as possible. A number of people who had found themselves caught up by arms of steel (which were not so comfortable nor romantic as some people seemed to think) and abandoned a split second later among the growing crowd of people taking shelter at the end of the Strip. So far, even with the opening offered by the blonde archer down below, Superman had not taken any lethal action against the creature, simply dodging its swipes and battering it back into the remains of the Bellagio fountain.
When the shield spun past him, he stopped in mid air, the cape billowing about his shoulders as he turned to see where the thing had come from. He stopped and stared for a second, and then he was gone. He waited a few seconds to see how the skinny kid with the webs did, and when he succeeded in his distraction, Superman slid through the air and stopped to hover about five feet up and six feet away from where Steve and Nell stood.
"We don't kill it or blow it up. We don't even know what it is yet," he said. He looked at the man with the big star on his shield and blinked. "Why does Daniel think you are so funny?" he asked, glancing over his shoulder as Spider-man dodged another blow.