Can I fold top pair if it's really low?

[cheburashka]

I’m in 3rd place with 12 remaining in a 1.20/45 (still working on rebuilding the bankroll lol).

UTG: (7295 in chips)
MP: (13741 in chips)
CO: (645 in chips)
SB: (3630 in chips)
Hero: (10310 in chips)

Blinds are 200/400/25, Hero is in BB with 6 [img]/images/graemlins/heart.gif[/img] 7 [img]/images/graemlins/heart.gif[/img]

One fold, MP calls 400, one fold, SB raises 400 to 800, Hero calls 400, MP calls 400. I felt that this call was justified by pot odds, since stacks are still pretty deep.

Flop (1325): 7 [img]/images/graemlins/diamond.gif[/img] 3 [img]/images/graemlins/heart.gif[/img] 4 [img]/images/graemlins/spade.gif[/img]

SB bets 400, Hero???

SB is 30/4/0.5, so I expect that his betting here means something. I don’t want Barry to call me a pussy, but I don’t want to be led down the primrose path by slow-played AA, either. I realize that I'm getting 4+ to 1, but I need more like 20 to 1 to justify looking for a set, and I think that given his passive play there's little chance he'll pay off if another 7 hits. Hitting a 6 would be better in terms of getting paid off, but I still don't like it.