Lex was, unfortunately, out of a gun at the moment. But he still had a brain, as screwed up as it was. He was smart enough to duck for cover.

"Despite what Jurassic Park insists on, T-Rexes had damn good sight." Or so most research he read suggested. "But they hunted more like sharks, and leaned on their sense of smell to hunt." Which meant that Samus was likely just a brightly colored rock to it, while blood-soaked Bruce was probably lit up like a Christmas tree.

"If those soldiers can bleed, they'll make an excellent distraction for it." Yes, Lex Luthor's helpful idea was to use the lesser enemies as a sacrifice to distract the greater one and they could get free.