After south's response of 6NT, I made a query. His response was "21 P".
His profile provided no bidding information.
Any reason for this bid?
What do u think is the ideal bidding sequence here?
Additional note: All pairs who missed the slam lose IMPs. There are, however, only 2 tables that bid slam on this hand. The other was 6♠+1, 11.6 IMPs and they at least bid less surprisingly than this one...

Help

Bidding
W N E S
- - P 1♠
P 2♣ P 6NT
P P P
Opening lead: ♦3
Result: 6NT+1
+12.2 IMP to NS