His mind was blank.
Normally Rex could conjure a plan from thin air. When circumstances were lowest, when he had no weapons, no contact to base, no chance of surviving, he would see with startling clarity what what to do next.
This time when he paused, took a breath and exhaled - he had nothing. He didn't care about the last mission, or the Torimbalo or whatever, and Jones was already dead so revenge was unnecessary.
Rex was empty.