15/30 LO8 weird turn card/action

[donger]

I'm having a ton of trouble reading these hands. Button is loose and bad (like 70/9/.51) and BB is loose and aggro and plays typical for these stakes. I have no idea why BB is checking this turn after capping flop.

$15/$30 Limit Omaha Hi/Lo
4 players
Converted at weaktight.com

Stacks:
Hero (<font color="#0000cc">$1485.00</font>)
BTN (<font color="#0000cc">$445.00</font>)
SB (<font color="#0000cc">$315.00</font>)
BB (<font color="#0000cc">$603.00</font>)

Pre-flop: ($25, 4 players) Hero is CO 4[img]/images/graemlins/club.gif[/img] T[img]/images/graemlins/club.gif[/img] 7[img]/images/graemlins/diamond.gif[/img] A[img]/images/graemlins/diamond.gif[/img]
<font color="#cc0000">Hero raises to $30</font>, BTN calls $30, SB calls $20, BB calls $15

Flop: 8[img]/images/graemlins/heart.gif[/img] T[img]/images/graemlins/diamond.gif[/img] 7[img]/images/graemlins/spade.gif[/img] ($120, 4 players)
SB checks, <font color="#cc0000">BB bets $15</font>, <font color="#cc0000">Hero raises to $30</font>, BTN calls $30, <font color="#cc0000">SB raises to $45</font>, BB calls $30, Hero calls $15, BTN calls $15

Turn: 3[img]/images/graemlins/club.gif[/img] ($300, 4 players)
SB checks, BB checks, Hero...