AK on bubble

[Norton]

2 table tournament, five of us left. I've got around 1800, and the other stacks are approximately 6000, 2000, 800, and 300.
Top 4 places pay.

Big stack is in the SB, small stack is in the BB, with the blinds at 50/100. UTG folds, and I find AKo and make my standard raise to 250. I've been playing tight, so this is usually enough to pick up the blinds, or get 1 caller. I'm hoping the BB will find a hand to throw his last few chips in on.

The button folds, but the SB reraises to 500. BB folds, and it's back on me. What should I do here? The SB has been very loose and aggressive with his big stack, so there's a good chance I'm ahead here. On the other hand, the small stack has surrendered his blind, and can't survive the next round of blinds. The only decent player at the table (besides myself) is the second shortest stack.

What would you do -- fold, call, or move in?