When you open a pack of raw chilled (not frozen) vacuum-packed meat, should you prepare the whole pack once it's opened? Can you prepare some of it when you open it and prepare the rest later or is this not safe?
The food safety rules for safety-atmosphere-packed meat (it is not under vacuum) are the same as for classically packed or unpacked meat. Once you open the package, you get 3-5 days in the fridge for whole pieces of meat and 1-2 days for ground meat. Please see How long can I store a food in the pantry, refrigerator, or freezer? for a list of "how long does it last" for most food types.
The difference goes in the other direction. As long as you haven't opened it, what counts is the date printed on the package, which usually gives you more time than the 3-5 days for unpacked meat.