Yes, that is what we assume her reason is. And if that is her reason it is certainly much less bad than capturing them for some selfserving reason. But I don't think that means it is not bad at all unless she truly had no choice (such as simply talking with them first). And I don't think that justifies her treating them badly post-capture.
I am no expert enough in the strip to answer what Girard would have done. i do seem to recall some anger by him toward Soon? Did he makie explicit threats, if so it might be reasonable to assume he would have carried those out.
If he had killed them that probably would have been an evil action. If he had captured them, mocked them, and ultimately released them (as Serini did) that probably would have been somewhat evil depending on context but may not have led to an alignment change depending on his other actions. If he had ignored them, rudely dismissed them, chased them off or similar that would have no effect of his alignment. If he had welcomed them, and taken the opportunity to let bygones be bygones that would possibly have been somewhat good.