I've interrelated these lines from Mass spectrometry by electron impact.
"In electron impact (EI) mass spectrometry the molecule is bombarded with highly energetic
electrons that knock a weakly bound electron out of the molecule. If you think this is strange,
think of throwing bricks at a brick wall: the bricks can’t stick to the wall but can knock loose
bricks off the top of the wall. Losing a single electron leaves behind an unpaired electron and
a positive charge. The electron that is lost will be one of relatively high energy (the bricks come
from the top of the wall), and typically one not involved in bonding, for example an electron
from a lone pair."
I can be wrong if this won't happen in the case of ionization. Because those loose electron can't be just vanished after being ionized , they should go to other molecules .