Reddit mentions of Stanley 2-10-099 Knife"99E" with retractable blade, Silver

The only way to make it yelling proof is to make a fully sealed box, top bottom and sides, which probably isn't practical. A couple of walls will help reduce sound levels though. I'd make it like a standard internal wall, frame it with 2x2" and cover it with plaster board. To prevent sound you need to fill all the gaps in the plaster. Try foam door strips or carpet between your wall and the apartment walls, ceiling and floor. You'll need to get a creative where the window is, maybe an old pillow stuffed in the gap? Watch out for condensation though. Once in place cover the inside walls with carpet.

Not sure of price, framing and plaster board are cheap, so are second hand doors from a demo yard. Hit up a carpet installer for offcuts or old carpet that's been ripped out. You could do the whole lot in a weekend with hammer, nails, hand saw to cut the framing and a knife to cut the plasterboard.