ya could try & setPos the moron!
INIT field code:
This setPos [getPos this select 0, getpos this select 1, 5.7]
where "5.7" is the HEIGHT for the guy (like if you want him to stand on 1st floor).
Then just slide the moron upon the building.
you could also put:
this setUnitPos "UP"; doStop This
in his INIT
=============
and then a trigger (fired by YOU, grouped to yer grp) could have the code:
[bob] join player
if the prisoner was named bob, he'd join ya when you got near.
Use the axis "a & b" to set the size of the trigger.