NJ: Undercover Police Officers

MAN:
Listen...

MAN/WOMAN:
(IN UNISON) We need to talk!

MAN:
Look, there's something I really need to get off my chest!

WOMAN:
Ditto!

MAN:
Something - which could potentially destroy our relationship!

WOMAN:
Double ditto!

MAN:
(SIGHS) You see...

MAN/WOMAN:
(IN UNISON) I'm an undercover cop!

BEAT

MAN:
You're kidding? What - you mean you're NOT an Islamist anarchist?

WOMAN:
And you're not in the Cornish Liberation Front?

MAN:
But I don't get it! How could this have happened?

WOMAN:
I guess we've been too busy bonking to have noticed.

MAN:
Wait a minute - if I'm assigned to you and you're assigned to me - who's keeping tabs on the bad guys?

FX: LOUD EXPLOSION

I really like this premise! There is probably a lot more you could get out of it too.

Very good - it works well at that length for me.

This is a great idea, love it!

I wondering would it be funnier if it was a cell of four people and they all slowly reveal their an undercover cop?

The one thing I'd say is push this more to develop it and get more humour out of it. How has it affected their relationship? Have they been trying to please the other person to curry favour but both wasting their time?

Great idea, let's have more!

I think there's a great premise here. You've gone for a simple set up and reveal but (along the lines Stephen suggests) there's plenty of performance you could get out of the characters in this setting that would deliver even more humour.