Just wanted to discuss how someone played

in a small live tournament this saturday.
I am UTG with about 6k chips
Second To act has 6k
2 off the button has 12k and has been a totally idiot calling with all sorts no understanding of position or feel for the table
SB has around 8k
Me and the guy in the SB have been moved tables [from the same table] and only seen about 3 hands since being moved.
Blinds are 75/150
I have

UTG and raise it up to 500 , Second to act flats it [who i know to be a bit of a rock] I immediately him on a monster the idiot 2 off the button calls :SHOCKED: .. The Sb then makes it 1200 [who i have recognised as a solid / aggressive player] this is a no brainer for me I give it a few seconds then fold [i am out of position with 2 to act and think i am behind to both] The

then makes it 3000 to play i wanted to discuss this play..because to me it makes it look obvious he has

but there is nearly 2500 in the pot and he doesn't have to see a flop. it also looks maybe like a 4-Bet with maybe 99 or 1010 to someone with no information..... Just wondering peoples opinions on how he played it.
As it panned out SB Flats with

it comes ten high he pushes

holds.