Electromagnetic and atmospheric braking

I was thinking of additional braking methods for landing on the moon.

Could we take a lava tube, surround the interior with an electromagnetic
coil, and use that for the braking action? I was also thing we could fill
the tube with a gas and use the gas for atmospheric breaking requiring only
a very small atmosphere. (We have to store our mined O2 somewhere, using it
for a braking mechanism for craft seems reasonable.)

(One downside is that the density of the gas will be higher at the entrance
than at the end...)

Tom M.
TomM@...