Players are allowed to rebuy through the end of Level 3. One can rebuy whenever one's stack is at or below 10,000. Thus, when a player busts, that player can at that time rebuy for 10,000 (for $5,000) or double rebuy to 20,000 (for $10,000).
Just before the break, Daniel Negreanu had just made another double rebuy to 20,000, and more than doubled up on the last hand of Level 2. So he sits with about 45,000 at the moment.