? for Greeny01

Greeny,

I respect you as player, having finished 2nd and 5th, respectively, in the last 2 tournaments. But on this hand, I'm perplexed as to why you called a late position reraise from the chipleader (who is a tight player) with ATo and then on the flop, an allin with a gutshot straight draw...

PokerStars Game #877043676: Tournament #3528786, Hold'em No Limit - Level V (75/150) - 2004/11/20 - 17:11:26 (ET)
Table '3528786 3' Seat #9 is the button
Seat 2: WLU River (3055 in chips)
Seat 3: Crazysteen (5005 in chips)
Seat 4: lucky2005 (5325 in chips)
Seat 5: greeny01 (3015 in chips)
Seat 6: CaptainBlood (1800 in chips)
Seat 9: garnetshark (5940 in chips)
WLU River: posts small blind 75
Crazysteen: posts big blind 150
*** HOLE CARDS ***
Dealt to garnetshark [Kd Kc]
lucky2005: folds
greeny01: raises 150 to 300
CaptainBlood: folds
Crazysteen said, "gg man"
garnetshark: raises 750 to 1050
WLU River: folds
Crazysteen: folds
greeny01: calls 750
*** FLOP *** [8c 9d Qd]
greeny01: checks
garnetshark: bets 1965
greeny01: calls 1965 and is all-in
Crazysteen is sitting out
*** TURN *** [8c 9d Qd] [Js]
*** RIVER *** [8c 9d Qd Js] [8d]
*** SHOW DOWN ***
greeny01: shows [Ts Ac] (a straight, Eight to Queen)
garnetshark: shows [Kd Kc] (two pair, Kings and Eights)
greeny01 collected 6255 from pot
*** SUMMARY ***
Total pot 6255 | Rake 0
Board [8c 9d Qd Js 8d]
Seat 2: WLU River (small blind) folded before Flop
Seat 3: Crazysteen (big blind) folded before Flop
Seat 4: lucky2005 folded before Flop (didn't bet)
Seat 5: greeny01 showed [Ts Ac] and won (6255) with a straight, Eight to Queen
Seat 6: CaptainBlood folded before Flop (didn't bet)
Seat 9: garnetshark (button) showed [Kd Kc] and lost with two pair, Kings and Eights

I don't mean to make this into an antagonistic thread, I just mentioned it because garnetshark is a member on my other forum, and I thought this was a hand worthy of some critical discussion.