make off

Miyuki MiyabeのCrossfireを読んでいます。
"You know how they say that even Buddha forgives three times and then gets angry? Well, since then no matter what the guy says Kayoko's stopped going back to him. Even when he threatens to kill himself on our doorstep. But you know, Chika-chan, the scary thing is that now it's like a state of war. And a guerrilla war at that"
"What's he saying now?"
"He wants to make off with my grandson," Izaki growled. "If he manages to get the kid, Kayoko would have to go back to him, right?"

"make off" は句動詞の様です。意味を調べます。
・Oxford English Dictionary: Leave hurriedly, especially in order to avoid duty or punishment.: they made off without paying
・Collins Dictionary: If you make off, you leave somewhere as quickly as possible, often in order to escape.: They broke free and made off in a stolen car.
・Cambridge English Dictionary: to leave quickly, usually in order to escape: The burglars made off before the police arrived.
この "make off" はこの後にも次の文で使われていました。
The thieves killed his mother and made off in the family's car with her younger sister as a hostage. Her body was found three dasys later.