This is the first hand of the last 8-board set of a KO, opponents are 42 imps down (which may explain some of what went on in both rooms). Your pass over 6D was clearly forcing. Without a large lead you probably would have bid 6H, by the way, but it seemed safer to take what money there was.
I'm not asking what you lead: the winning lead is a club.
The really difficult questions are:
- why is a club right?
- if you lead a major you concede 1090 and gain 7 imps. What on earth is going on in the other room, given that they are trying to swing but haven't been absurd?

Help

3♦ P 5♦ x
5♠ x P P
6♦ P P x
all pass