Chuck "MacGyvers" a refrigerant line to super cool the metal chain of the handcuffs to break the metal. This would not be possible because standalone refrigeration systems never use flexible lines to hold "freon" and second the cooling temperatures of standard refrigerants is not cold enough to reach the -130°C needed to make nickel alloyed metals brittle enough to break.
When Chuck flashes on the location of the FULCRUM training center it says 1919 Mulholland Street, but Chuck tells John and Sarah that it's at 1919 Mulholland Drive.