WTF?! How does a straight LOSE to 2 pair?

Starting Hand
Dealing pocket cards: [5h, 4d]
jim j 45 raises $100
Ollie_Hold raises $275
ECI folds
jim j 45 raises $400
Ollie_Hold calls
Dealing flop: [Qd, 2d, 3s]
Ollie_Hold bets $600
jim j 45 raises $1,200
Ollie_Hold calls
Dealing turn: [6d]
Ollie_Hold bets $750
jim j 45 calls
Dealing river: [4c]
Ollie_Hold shows [Tc, 3c] for a pair of threes
SHILL shows [5h, 4d] for a straight six high
jim j 45 shows [Qc, 6h] for two pair, Queens and sixs
jim j 45 wins main pot $4,975
Ollie_Hold stands up
SHILL stands up
SHILL takes a seat