Gillian Anderson had a “panic attack” when she watched a particular scene in “Teenage Sex & Death at Camp Miasma” in a cinema for the first time. “That blood day,” as she calls it, “was pretty serious… just remembering the amount of liquid and how to not drown while shooting the scene… it was a lot!” Without giving too much away, the scene in question comes towards the end of Jane Schoenbrun’s wild, hilarious and emotional psychosexual exploration of horror, fandom, identity, pleasure, trauma and awakening, the apex of a rousing crescendo of sublime, almost-magical delirium. And yes, there’s a whole lot of blood. But it was Anderson’s co-star, Hannah Einbinder who was really suffering that day. Popular on Variety “We shot a lot of very intense stuff and I had to really put myself in the fear and approach it incredibly seriously,” the “Hacks” star tells Variety .…