Trying to make sense of the Zam/Fett/Poisoned bugs thing.
What if Zam is hired by Gunray directly to kill Padme and use the droid, operated by remote to do it (we already know that the Feds use battle droids so no need for bugs).
It opens up a hole in the window, takes aim and Anakin rushes in just in time to deflect the shots.
When Kenobi jumps onto the droid she tries to smack him into buildings using the remote and then self destructs it.
Fett kills Zam under orders from Dooku who is trying to control Gunray's quest for revenge because she is one of the few Senators trying to stop the escalation of the war.