This is the picture that might prove that the liars are there for Mona, rather than Lesli. She knows something and based on her acting normal, this could be her new lair and it would be a perfect cover up.
Mona does not look impressed. Throughout these stills from the episode, she is the only one who has remained calm and that raises our suspicions that she is back to being the master manipulator. Did she ever have a break?!
Spencer and Hanna are back out of hiding and ready for the truth, but where exactly is it? I'm will to guess that some part of it will be in that cage. Are A's threats tested on animals? I wouldn't rule it out on this show!
Mona has a Radley Sanitarium case file, but could it be Lesli's? You can bet your bottom dollar it is! It may seem like Mona has come to her senses, but don't rule out the possibility that she has manipulated the contents of the file.
It sure looks like Mona is back to just popping up in random places. It remains to be seen whether she is on team Lesli, or team liars. Either way, look for some choice words thrown her way from the liars.
Hanna and Spencer are stealthily infiltrating some sort of laboratory, but why? Considering we know they are going guns blazing after Lesli, my best bet would be it's connected to proving she is their tormentor.