live 5/10 game with incredibly weird preflop action holding 77

[mindless]

From about two weeks ago, I'm playing 5/10 and have been more card-dead than I've ever been in my entire life. The game is pretty good and playing very deep...there are at least four stacks over 3.5k (1.5k min buyin). About two people limp to me and I just limp with 77 in middle position and maybe 1200 behind. A very deep stack (~6k) limps, and then a very tight button raises to 75 with about 3k behind. SB folds, BB thinks for a second and calls 75 (he's got around 4k and is very very loose). One of the limpers folds, and then another limper calls. I call, but then the very deep stack, who I can't quite get a read on but is playing somewhat tighter than the rest of the table, raises to 500 straight. The button looks at him like "WTF?" and then thinks for bit and calls. BB thinks for a minute and calls. Limper hems and haws and folds. I folded, as I didn't have much more money on me at the time, though bankroll isn't an issue, but my question is:
1) Ignoring variance, should I be calling?
2) If the other limper calls, I could be calling, right?

There's about 1600 in the pot and I have to call to 425 more, and given that I've got about 700 left after that, it seems like it's definitely going in, so I'm putting in 425 to win 2800 assuming I get at least one postflop caller, which isn't quite the odds I want, but someone else might call as well (though I could get set over setted). If the other limper calls, it's putting in 425 to win 3200, which seems a little better but not quite.

Thoughts? Also, given that I'm not playing that deep, pushing seemed like a terrible option, since while the reraiser to 500 might be making a play, the button almost certainly has jj, qq, or maybe ak, but I doubt I can get it heads up with just him. Agree?