Hand from the ME of the World Poker Open

[Gigabet]

Level 4 (200/400)
Stacks are close approximations.
Seat 1(t30,000)
Seat 2(t8,000)
Seat 3(t20,000) (Me)
Seat 4(t75,000)
Seat 5(t26,000)
Seat 6(t12,000)
Seat 7(t40,000)
Seat 8(t8,000)

Seat 1 is the button, I am the BB(seat 3). I post 400 and am dealt...
(7h4d)

Seat 4 folds
Seat 5 (t26,000) Raises t1600, t2000 straight.
Seat 6 (t12,000) Calls t2000
Seat 7 (t40,000) Calls t2000
Seat 8 folds
Seat 1 (t30,000) Calls t2000
Seat 2 SB folds
Seat 3 (t20,000...Me) Calls t1600

flop (7s Jh 7c)

Seat 3...I check
Seat 5...Checks
Seat 6...Checks
Seat 7...Checks
Seat 1...Checks

Turn ( Qh )

Seat 3...I Check
Seat 5...Bets (t4000)
Seat 6...Raises All-in (t12000)
Seat 7...folds
Seat 1...folds
Seat 3...I Reraise All-in for a total of (t20,000)

Seat 5(t26,000) goes into the tank for about 2 minutes....and finally calls, making the comment "I just can't fold this hand."

The chips went into the pot and the dealer shoved them together, before creating a sidepot, so that had to be taken care of before we flipped our hands over and ran the river. So I had time to contemplate my demise. I say to the table, "there is absolutely no way my hand can be good."

Eventually the hands get opened, and Seat 5 opens QT, and Seat 6 opens AA?!?! This is the 4th level of the Championship event of a WPT event. Both Seat 5 and Seat 6 are touring players.

Please explain what was going on in this hand, it flew way over my head.