Everyman Cinema, Level 4 Trinity

Second floor (stairs and lift), past the reception/bar desk and pizza area, right to the back, down a hallway to the left. No stairs, gender neutral toilets are in one bathroom (several stalls), with disabled toilet next to it.

It's usually quite busy, so you'll likely go unnoticed for using the bathroom only. There's a balcony near the bathrooms, so it could look like you're going there. People go to eat the pizza as well as for the cinema, and people often go to the bathroom before eating.