Explain This "Barney Miller" Joke

I was watching an episode of *Barney Miller *and Dt Fish walks in to the precinct and says to a man “Can I help you?” The guy (who turns out to be a bomber) says “Can I help you?” Fish deadpans and says “What can be done, has been done.”

The audience laughs really hard and you hear clapping.

Is this some kind of an inside joke or a line from a movie. I know they make a lot of jokes about Fish being old but it seemed to get too big of a response for a joke about age.

Does it reference something from earlier in the episode?

Other than that it seems like Fish is saying he is beyond help.

Yep, not having seen the show for a quarter century, I chuckled - it’s just such a *Fish *thing to say. Nothing can be done for him, it’s all been tried and has failed.

It occurs right in the beginning of the show. I was thinking maybe it was a famous line from a movie of the time or TV show of the time. It was one of the earlier Barney Miller episodes 'cause it still had Chano (Gregory Sierra) on it

I also thought it was a reference to Fish looking like 500 miles of bad road. Don’t forget, People magazine once mistakenly reported Abe Vigoda as having died.

According to abevigoda.com he’s still alive.

I agree, it pretty much means that Fish is beyond help; there’s nothing that can be done to help him.

I concur with the other posters. The joke is that Fish has been rode hard and put away wet, so what can a bomb do now, oy?

My problem is that damned IQ test ad thingie. How many triangles, yada yada, and the potential answers are:

25
35
45
48

None of these are correct. There are 26 triangles by my count.

barney miller. wow. just…wow

Except, IIRC, the bomb hadn’t yet been revealed.

I think Fish is just repeating his personna, that he is beyond hope. No one can help him anymore, since what can be done, has been. It was a comic retort to a straight line. It’s just a funnier dialogue than:

“Can I help you?”

“No, it’s too late for that.”

Fish is roughly the equivalent of Eeyore from Winnie the Pooh–he’s gloomy, pessimistic and has a deadpan expression and delivery. I laughed just “hearing” the quote.

It’s fairly close to the “the bearer has done what has been done” line in the culimination of the 1973 version of The Three Musketeers
Are the two shows close enough in time the audence would have seen it as a spoof?