Observed 10/20 hand Boosted and Samh

[craig1120]

Ok someone IM'd this hand and I have my own opinions and thoughts on it but was wondering what some of you guys think of Boosted's river c/r. What do you guys think he is doing and why?

Full Tilt Poker Game #3254589111: Table Supreme (6 max) - $10/$20 - No Limit Hold'em - 21:12:21 ET - 2007/08/14
Seat 1: SamH133 ($4,528.50)
Seat 2: MITTurk ($2,752)
Seat 3: JAB81 ($248.50)
Seat 4: jenn415 ($3,917.05)
Seat 5: Boosted J ($1,880)
Seat 6: JeffreyAlan ($2,000), is sitting out
JAB81 posts the small blind of $10
jenn415 posts the big blind of $20
The button is in seat #2
*** HOLE CARDS ***
Boosted J raises to $70
SamH133 calls $70
MITTurk folds
JAB81 folds
jenn415 folds
*** FLOP *** [Ah 5s 6d]
Boosted J checks
SamH133 checks
*** TURN *** [Ah 5s 6d] [Jd]
Boosted J has 15 seconds left to act
Boosted J bets $170
SamH133 calls $170
*** RIVER *** [Ah 5s 6d Jd] [Ts]
Boosted J checks
SamH133 has 15 seconds left to act
SamH133 bets $400
Boosted J raises to $1,640, and is all in
SamH133 calls $1,240
*** SHOW DOWN ***
Boosted J shows [Qs Qc] a pair of Queens
SamH133 shows [Ac Tc] two pair, Aces and Tens
SamH133 wins the pot ($3,787) with two pair, Aces and Tens