Callidus Assassin - Polymorphine questions

Polymorphine states that when a Callidus assassin arrives from reserve to choose a unit, and that unit suffers D6 S4 AP2 hits. It doesn't say anything about the unit having to be outside of combat, or a legal shooting target. The FAQ specifies how to handle the callidus popping out of a squad and wiping the squad out, or how to pop out of a vehicle, but nothing is mentioned there about close combat either.

Can a Callidus Assassin pop out of a squad that is currently locked in combat, and deal his/her/its free D6 hits?

If so, can the squad claim a cover save if the combat is not in area terrain? The assassin is not on the board (in effect, he/she/it is in the midst of the squad itself), so there's no way to determine if the other unit(s) in combat are actually intervening models.

Can a model with an additional save "in close combat" such as a wych's dodge, a nemesis force sword, or the Swarmlord's parry, be used against the free swings?

After applying the damage, can a Callidus assassin arrive by deep strike without scatter in a location that would intentionally force a mishap, and just roll on the mishap table? (I don't see this being a good idea often...)

I think I would lean towards not being able to. Only because targets locked in combat are not eligible to target.

- Since it just says to nominate a unit, I'd think it could be any unit.
- I don't see where that is denied.
- I'd say no.
- I'd say yes. You are nominating the unit yourself. The rules for those saves just say in close combat, which you are in. I'd say that if you don't want those saves taken, pick a different unit. :)
- It says it has to be placed -- I don't think you can place a unit someplace that would trigger a mishap, except within an inch of an enemy unit. I'd say no to this one.

I say yes please to assassin cheese.....it'll go great on crackers with psyko grenades

Well you'd have to simul-charge but running a Calli into an assault with another unit with a grenade caddy would be hilarious.