An expert of “12 angry man”

“[Some of the jurors are taking off their jackets. Others are sitting down at the table. They still are reluctant to talk to each other. FOREMAN is at the head of the table, tearing slips of paper for ballots. Now we get a close shot of NO. 8: He looks out the window. We hear NO. 3 talking to NO. 2]

NO. 3: Six days. They should have finished it in two. Talk, talk, talk. Did you ever hear so much talk about nothing?
NO. 2: (nervously laughing). Well… I guess . . . they're entitled.
NO. 3: Everybody gets a fair trial. (He shakes his head.) That's the system. Well, I suppose you can't say anything against it.
[NO.2 looks at him nervously, nods, and goes over to the water cooler. Cut to shot of NO. 8 staring out window. Cut to table. NO.7 stands at the table, puffing out a cigarette.]
NO.7: (to NO.10). How did you like that business about the knife? Did you ever hear a phonier story?
NO.10: (wisely). Well, look, you've gotta expect that. You know what you're dealing with.
NO.7: Yeah, I suppose.”

Question
Juror #10 says to Juror #7 “Well, look, you've gotta expect that. You know what you're dealing with.” What does Juror #10 mean here? What prediction can we make about Juror #10’s biases