“whatever is good in your eyes.” Here, this is a problem. The Judges period was a time when every man did that which was right in his own eyes, but here we see that that kind of thinking and behavior can lead to very evil and ungodly acts.
“Abuse them.” The Hebrew word has more the meaning of “humble” or “humiliate,” not “rape,” so the man is understating what he knows would happen to the girl if the crowd gets ahold of her, and indeed they did rape her, in fact, raped her to death. There is a stronger word that means “rape” in Hebrew (cp. Isa. 13:16; Zech. 14:2), but the man did not use that word.