After dying, I respawn at RED base, only to find that the briefcase is not physical matter. I decide to begin hacking, and start at the passcode of the laptop. Just got let my hack go through all possible codes...
[A FEW DAYS LATER]
Done! Next I find the Briefcase is in a series of various of folders. Gotta let my hack go through that, too...
[3 WEEKS LATER]
Done at last, done at last. I convert the briefcase back into physical matter the size of a 5*5 inch cube. I lock the cube in a safe inside another safe inside a laser field inside another safe inside another laser field surrounded by fire. I ask my team to help me, as I become an engineer, along with 5 others, building sentries around said safe. The demomen put sticky bombs all over the area the safe is at, and the rest of the team is ready to defend.