hi, i'm a bit confused as to what you mean. If you just want to download a leaked data base from like a forum, just conect to some internet, download it and then disconnect the internet before opening the file so that no reverse shells or meterpreter sessions can start if there is a virus in the file. If you mean you want to hack a data base and then download it would be a bit harder. I wouldn't use public internet, not were i am anyway because public internet has retrictions on it and everything you do on your computer while using the public internet is recorded. If you were to use tor, whoever owns the internet might not know what you were doing but they would now that you were using tor and come after you for that. The best way is most likely to use a internet connect that you could get disconected after or hack some elses internet and use that. Also use a VPN and procy chains if you can. Now do this for the most safety. Download the data base on to a external hard drive. Then once you have finished downloading take the battery out of the computer you used and throw the computer away. Make shore not to leave any finger prints on the computer and scrub off any serial numbers. Also don't have any mobile phone on you when you do this if you haven't already done it.