A psych backfires in the Spingold

Holding the South hand Vul against not, what is your bid? Nick Nickell found the magic psyche, a steal of ONE SPADE, shutting his opponents out of the spade fit. In fact the spade game made with a overtrick at the other table when Meckwell was +450.
Now, after Katz innocently raise to TWO SPADES, Nickell bid FOUR HEARTS.
The bidding tray stayed under the screen agonizingly long, and came back with FOUR SPADES! (Katz had taken FOUR HEARTS as a SPLINTER in support of SPADES, which it was in their partnership). Nickell corrected to FIVE HEARTS. More agony. No escaping with rebids in the modern bidding world. This was interpreted as Exclusion Blackwood (asking for key cards outside of hearts) and the bidding tray came back with SIX CLUBS. Now came SIX HEARTS doubled, and defended softly for -500. The loss being "only" 50 total points or 2 IMP. Instead of a possible double game swing or game swing.