Board Pairs Big On The Turn - Now What?

[dr_zorba]

I had a nasty hand tonight that is still bothering me enough six hours later to post my play and invite another shower of flaming mockery in exchange for the wisdom of the good players.

About 20 minutes into a $10 MTT (slumming for most y'all).
Blinds 20/40, 9 seated, OTB has ~t2000, SB has ~t1200, BB (Z) has ~1700.

OTB won a good hand early without a showdown (strongly bet) and has been quiet since then. SB has been playing a lot of hands, usually Limping.

OTB Limps, SB Completes, and Z raises to 80 with A9s. (Amateurishly small? More?? Check???)

Flop is AK9 [r] (t240)

SB Checks, Z bets 150 (More?? Less???), Both Call.

What should I be thinking at this point? I remember thinking that probably one guy had a strong King and the other one a weak ace (since I didn't raise very much PF and nobody came over me, yet both called the 150).

Turn is another King and SB Checks. [AKK9] (t690)

I freeze. Before I know it time runs out and my hand auto-checks. (You get about 15 or 20 seconds.)

OTB bets 400 (immediately, without hesitation), SB Folds, and again, paralysis and indecision. My time runs out for an auto-fold.

I'm not sure what happened to my brain but it just seemed to stop working after the Turn. When the board paired Kings, my hand just started screaming "I'M NO GOOD - DON'T BET ANY MORE!" Does this sort of paralysis ever happen to experienced players? Was the Check-Fold (by FORCE!) actually best play by accident?