Look at the raiser's mindset. Raiser knows that BB will call because the blind is half his stack. He also knows you'll fold anything to make the money because BB is about to get knocked out. So if he raises, it will be his 2 cards verses BB's random 2 cards. I'd be slightly worried about raising into the big stack, but apparently he wasn't, so he probably has a slightly better than average raising hand. I'd put him on any A7+, K10+, Q10+, any pair>6. From his point of view, I agree with the raise. He's holding a better than average hand verses one random hand, which he can assume is average.

For your mindset, you have to think this through. You are way ahead of most of the hands he could raise with, and only behind to KK, AA, and only slightly ahead of AK. You're looking to double up, and I see this as the perfect opportunity. The only way I fold here is if raiser has been a rock, only raising high pockets or AK.

With only 900 chips, if you don't call this, there is a good chance you're third place.

The three way pot isn't great, but only 280*3 of it will go to the BB if he wins and you can still almost double up. If the BB had a big enough stack to hurt you, he has a big enough stack to fold to 2 all-ins.