What are the loop holes in the story THE MERCHANT OF VENICE?

Unable to find any loopholes, Portia grants Shylock his pound of flesh. Shylock, overjoyed at winning his case, holds a knife ready to cut into Antonio's breast.

Portia stops him by asking if he has a surgeon present to suppress the flow of blood. Shylock tells her that the bond said nothing about providing a doctor. She informs him that he may have his pound of flesh, but that if he sheds a single drop of blood then Venice can take away his lands and wealth according to the law. Shylock, clearly unable to comply with this law, asks instead that he be given the six thousand ducats. Portia refuses his request, explaining that she has already ruled according to the contract, and that it must be carried out.

Portia then starts to read the contract literally, reaffirming that Shylock must take exactly one pound of flesh, no more and no less, or he will violate the contract and die. Shylock tells the court that he wishes to completely drop his case and forgive Antonio the entire three thousand ducats. Portia again refuses his request, explaining that the law in Venice states that if any foreigner conspires against the life of a Venetian, half his wealth is to be given to the man against whom he conspired, and half is taken as a fine by the state. In addition, the Duke is granted the power of life and death over him.