We know almost nothing can scare emerald in halloween, whit all those monsters looking like aliens from another planet. But... how do she handle psicological horrors? (Like silent hill, coraline, zalgo).
Yeah I guess she might be accustomed to alien species. I have the hc she built her fame by fighting one in particular (hinted this in an old comic, but won’t say more not to spoiler). She might be scared by gem experiments and the cluster - plus the mysterious “harvesting”!!
However to reply your question she looked so stressed for losing a ship, and I like thinking the reason behind this is that she fears abandonment in general, so since a lot of psychological horrors use this for their main characters she might find them unsettling!