MacGyver Science: Rails + Pitons + Pulley + Pipe + Salt
DYI Cutting Torch
We start off with Desi inside some type of chamber. The air pressure is decreasing — that means that the density of air is getting to the point that there’s not enough oxygen to keep Desi alive.
MacGyver runs off to grab some supplies. He comes back with some jumper cables and a car battery.

The key here is the two carbon rods to connect to the jumper cables. He pulls these out of zinc-carbon batteries (the same one’s I used in this arc-lamp).
This is basically an arc lamp, but he uses the arc to cut through door lock and get Desi out.
Build a Train Car
It’s not really a train. It’s basically a handcar with an engine instead of hand-cranks.

If you get a flat track, pretty much any small engine would be enough to get the thing moving. What about the wheels? MacGyver uses some old car rims — this might work if the track is straight. However, real train wheels are beveled. Check out this cool activity.
Screw Jack
It’s one of the basic types of simple machines — the screw. MacGyver uses a literal screw jack (the jack to lift up a car) along with some jumper cables. He connects the cables to a steering wheel and runs them around a tree with the jack. Like this:

The screw jack is fairly simple to build. Here is an example.
DIY Climbing Harness
It’s just a plain build. MacGyver makes a harness from car stuff. Check this out.
Luge
Really not much to say here. MacGyver uses a metal sheet as a luge to slide through a tunnel.