The survivors had rildes to spare so its possible Lizzy got her hands on one.

And now for a gun Lesson!
there are a couple types of jams, but i will cover two of the major and well known ones.
One where the empty shell fails to eject from the chamber (common and easily fixed)
The second is where two bullets try to enter the chamber at once, creating a "double feed" these are hard to fix but not impossible.