When do you presume she knew they were trying to flee? How do you know that she was trying to block their escape? She doesn't know the way out as it is. She only attacked when they attacked her, and this isn't the first time they destroyed one of her homes.
You can see this in multiple ways, killing some of them sends a message to stop fucking with her. Trying to kill all of them means that she could also be worried of the survivors being able to lead bigger parties towards her location (which has already happened to her in the past). There's safety in leaving no witnesses. She could've also meant to not kill anyone, but they attacked her and she underestimated her strength and overestimated that from humans, she did appraisal on the most powerful human wizard after all (who was later doing a massive spell)... and mix that with being angry as fuck, those are the results.
Heck, she doesn't seem aware that they can't understand her or hear her. For all we can tell, they ignored whatever she was saying and attacked her so she defended herself.
But we didn't get her POV, just her aftermath rationalization, something she always does when things don't go quite the way she planned them.
In the end, they were enemies and attacked her. She fought back, don't know more than that. She's been in constant danger and trying to survive since she was born, if you can't sympathize with that just because this time around the enemies were humans... well, that's on you.
Other than that, my appreciation is that she doesn't particularly care about humans, as in she's indifferent to them.