$5 - Push this AQo HU?

OK, the villian had long been a cheapleader, having taken out AA and AK in the same hand when his TT (all money in PF) flopped a T. Then the 3rd place guy was disconnected, so we both picked off his blinds and it had been HU for 5 hands, nothing particularly exciting had happened till here: What's you call? Push, Call or Fold...

POKERSTARS GAME #3126776225: TOURNAMENT #15462577, HOLD'EM NO LIMIT - LEVEL VI (100/200) - 2005/11/22 - 10:53:24 (ET)
Table '15462577 1' Seat #8 is the button
Seat 6: ckna (9425 in chips)
Seat 8: HERO (4075 in chips)
HERO: posts small blind 100
ckna: posts big blind 200
*** HOLE CARDS ***
Dealt to HERO [Qs Ad]
HERO: raises 400 to 600
ckna: raises 800 to 1400
HERO: .....