Is it safe to wait 2 weeks with a broken foot, for surgery?

Depends on the case.: Surgery should usually be attempted shortly after the initial injury. In certain circumstances such as severe fracture blisters it is recommended to delay the surgery for al later time.

Foot: Yes, depending on the type of fracture and the type of surgery needed. When the foot it's too swollen it is recommended to wait until the swelling comes down and it's safe to perform an open procedure; two weeks is acceptable to perform surgery. If the surgical wound is closed under a lot of tension it might open and then get infected.

Surgery: Yes - some cases of fractures needing surgery are very swollen . If that was the case then waiting for that to decrease is correct so there is not excess pressure on the wound post operatively that could result in wound dehiscence and / or infection.