Alex tilted his head a bit. When she asked if he was nuts a very smartass remark of maybeand walking nonetheless popped into his mind. Probably not the best call though.
".... Exactly, we must discover whats causing this...." Alex says, confident he can probably kill anything that he would come across. Alex looked around and the lack of life was strange. Strange, but something out of place would not stop him. ".... Come on we have to find out what happened, if we stay here we'll probably never know." Alex said tapping his foot repeatedly wanting to just find out, Curiosity overwhelming everything else. A peace of a sort had been made that cant be found on earth. He must go look for the cause. "What do you suggest we do?" Alex asks. The forest was all around the cave. They could not stay on the cave forever. 
He could become so child like at times. He didnt like be restrained. Especially from discovering knowledge.