The slug is the obvious choice here. Although shot acts much like a slug at close range, it's not going to penetrate as deeply.
It depends on where you put the shot, and how close you are.
The reason I said that, is the presence of large quantities of fat, and hair. On a large diameter, but light, and relatively slow projectile, that's going to make a big difference, if you can't manage say a head shot a foot from the barrel.
If you were to for example hit a shoulder bone, expect a few scratches, and maybe a few tooth marks when they examine your corpse.
A small lever gun like the model 94 Winchester trapper in 30-30 would be a better choice.
You can take the butt stock off for the flight.