I'm probably just overthinking this, but can I ask, is the -ta' necessary here? As I understand it, -ta' indicates that an action has been completed, and was undertaken with intent. So is it the case that we always refer to an arrest as a completed action, even if it hasn't yet occurred? Or is this sentence saying that the arrest process was started but not finished? Thanks so much as always.
You are always allowed to use -pu' where you could use -ta'. When you use -pu', it doesn't mean the action completed without intent; it means the action is completed, and whether there is intent is not mentioned.
(I'm going to add a ghaH to this to avoid certain ambiguities and overly broad translation possibilities.)
wej ghaH qoplu'ta' He/she has not been arrested yet
Implies the arrest envisioned is to be completed intentionally.
wej ghaH qoplu'pu' He/she has not been arrested yet
Only envisions a completed arrest; does not specify whether the arrest is completed intentionally. It might be or it might not be.
Also, the "intention" of -ta' is not the opposite of 'accident." -ta' implies the subject set out to accomplish the action and did, in fact, do it. If you do something illegal and a cop witnesses it and arrests you on the spot, whether the arrest is "intentional" is a matter of focus. The cop didn't seek you out with the intent to arrest you. On the other hand, the cop did willfully move their legs and arms to perform the movements involved in arresting you. Unless you were discussing the biological events that occur during an arrest, this kind of "intent" isn't really what you mean. -pu' would be much more appropriate in a case like this. Something that is completed accidentally certainly doesn't merit -ta', but there are non-accident times where -ta' is also inappropriate.
With wej ghaH qoplu'ta', I read it as the speaker knowing or expecting that someone is looking for him/her to arrest him/her, and it hasn't happened yet. I don't read it as him/her managing not to be caught yet by any random cops who happen to be around.
P.S.: wej ghaH qoplu'ta' could also refer to an intentional arrest that hasn't been finished yet. He/she is in the process of being arrested, so he/she isn't completely arrested yet. You might say it in a context like "You can't lock him up yet because you haven't even finished arresting him."
Thanks very much, that's really helpful and a good context for the difference between -pu' and -ta'. One last question, would it ever be appropriate to say wej ghaH qoplu', without any suffix indicating completion? Or would that be an ungrammatical attempt that roughly translates to no one yet arrests her?