Commit to TP/weak kicker with medium/low M?

[ras52]

Third level of a $20 B&M MTT. My stack is ~4250, blinds 100/200, so M a little over 14. Button limps, SB completes, I check in the BB with Q4o. Flop Q-x-x with two spades, pot = 600. SB checks, I bet 500, button min-raises to 1000, SB folds.

I've been at this table for less than an orbit, so I can't interpret the button's limp, although the table has generally been passive PF so far.

I'm getting > 4:1 to call and see the next card, but I don't want to get sucked into a commitment to this hand. Having said that, my M is sliding and I'm feeling under pressure.

Fold/call/raise?