A priest, a doctor and a lawyer go into a bar... What's the punchline?

[Scruff]

Well, I guess the pool room is for fun - so let's have some.

A priest, a doctor and a lawyer go into a bar.

The lawyer says to the priest "first shout's on you".
The priest buys a round and they all drink.

The priest then says to the doctor, "your shout".
The doctor buys a round and they all drink.

The doctor then says to the lawyer, "your shout".
What happens next?

(And don't ask me - there's no tricks here. Just post the funniest punchline you can think of. If you can't think of one, vote for your favorite by clicking it's "Like" button.)

 

[Rob Legat - SBPL]

The lawyer agrees, pays for a round of doubles, quietly enters it as billable time and outlays, and makes a diary entry to follow up the priest and doctor for ‘work licence due to drink driving’ charges on Monday.

 

[Scruff]

Hilariously brilliant!!! - thanks Rob.

 

[Scruff]

@Rob Legat - SBPL - Well mate, it seems that no-one else is gonna top your answer, so I guess you win!!!

If we ever meet, first round is on the musician sitting in the corner laughing his a**e off (which would be me by the way).