Moved up Bump() in silicon.dm, and tested it.

According to my tests, unachored AI and Borgs behave as normal when
bumped by a mob.

A human can swap places with a borg if both have help intent on when
moving...
But a borg can't swap places with a human if both have help intent on,
if it's the borg that's moving. Apparently it's a normal behavior,
tested it on Sibyl.

AI don't have intents so they just get pushed.

pAIs aren't affected by bump, as they seem to act like as objects when
walked over or thrown.
Decoys seems to be some old MALF module that isn't in use anymore, so I
didn't touch it.