The motive is slightly funny, but the turning point saved the film

Madalyn Urlanger: [regarding Corey] Ah, yes. I remember him vividly. He was in a terrible hurry. No D in his name, unlike my second cousin or whoever he is. Rush, rush, rush. He simply took something out of his safe deposit box and literally ran out of here. No private cubicle, nothing. He didn't even take his key. I've never seen anything quite like it.

Ella Crystal: Did you see what he removed from the box?

Madalyn Urlanger: Oh, we're not allowed to do that. Our customers are guaranteed complete privacy.

Ella Crystal: I appreciate that, Ms. Urlanger.

Madalyn Urlanger: Miss Urlanger. I never quite liked "Ms." Sounds like a beehive.

Ella Crystal: [after a chuckle] Uh, you say he reached for the box right in front of you. It's possible that you saw what he removed because you couldn't avoid it, isn't it?

Madalyn Urlanger: Well, now that you mention it, maybe I kind of saw something. A plastic thingy with something inside.

Ella Crystal: A computer disc, maybe?

Madalyn Urlanger: [nods] Maybe.

Mark Hunter: And after you saw the man with the knife, what did you do?

Kevin Tarlow: Oh, I didn't have time to do anything. Oliver just-

[gestures movement]

Mark Hunter: Excuse me. Oliver?

Kevin Tarlow: My dog. He's a Jack Russell terrier just like the one on Frasier. They don't know they're small. They're absolutely fearless. It's amazing really.

Mark Hunter: Mr. Tarlow, what happened after you saw the man with the knife?

Kevin Tarlow: Oliver just ran up and bit him.

Mark Hunter: Where?

Kevin Tarlow: On the calf of his left leg. And Jack Russells have very sharp teeth.