Hm, no wonder something kept nagging at me. That was a long while ago though, so it shouldn't be a surprise when I say I didn't remember that detail.
If bows weren't explicitly marked as weapons that need two hands to effectively wield, I'd let this happen. But given they are, that label disallows the holding of a dagger in wielding ready position in the other hand, requiring an object interaction to actually make it work. Could hold the bow in one hand if you weren't attacking with it though.
This means the desired objective could be achieved had you prepared the dagger on your last round after taking the shot. No need to even drop the bow if the dagger flies, she runs to another and tosses that. You did mention her considering using a dagger back then. Perhaps she did a little more than just considering?
@NorschtalenEDIT: Hm, but then again, is that two-weapon fighting any longer with the abolishing of the concept of the off-hand… so it could be made work with the dropping of the bow if the dagger was prepped last turn.