Do you honestly think she didn't feel safe around him or was she trying make him look like a threat to keep him away from the group.
It could just be me but Layla doesn't really like or try to understand anyone that is different.
The only Abnormality is the incapacity to love
I got the impression that she felt uncomfortable around him because he was different and she didn't know how to deal with that, and that in turn caused her to exaggerate how threatening she found him.
I don't know whether she actually felt like he was going to hurt her, but he definitely didn't fit in with her idea of how people should be. Her references to the 'perfect' baby she and Michael were going to have and her frustration with Kyle for not being a good conversationalist left me thinking this was more like an obsession with an ideal (and those purist overtones creeped me out a little) and because Shrek didn't fit into this ideal, then she did feel threatened by his presence. Maybe not physically, but definitely ideologically.
I've just come off of an All The Small Things marathon, and I found myself wondering about this all the way through. Layla's a much more fascinating character the second time around, once the loathing has simmered down a little...I'm wondering if she was always like this, or if this obsession with perfection is some kind of attempt to purge herself of the guilt from her boyfriend's death?