It's Texas No-Limit Hold'em

You just bet! Someone raises all in.

You look at the board and see the flop.. 5-5-7

You hold 6-7

You are trying to decide to call the all in for all of your chips.

After a minute or three of deep thought the all in hand turns over one of his hole cards. It's an Ace.

The deep thinker puts him on Big Slick or AQ and makes the call for all of his chips.

Now the first re-raiser shows his other card...another Ace.

Did the fella that showed his first Ace violate any of the rules of poker. I was not involed in this hand ( No I was the lucky one that went all in with pocket queens trying to win a large pot before the blinds only to get called with KJ offsuit and have the caller hit 3 more kings )sorry I can't seem to get past that beat!

So then...is it wrong for someone to show one card to the table when the hand is still to be decided?

Thanks in advance for any clarifiacation.