This creature needed a proper examination, he had to get him to his lab. Unfortunately this bat was intelligent which meant he would understand what experimentation means, which could mean that there would be an ethical issue. That really didn't mean much to him, but people could get bend out of shape. Fiona might punch him again.

"Why don't we take you down to the kitchen little bat. Maybe find you a nice snack?" That should confuse it enough for him to knock him out.