At least I've managed to find out the reason for the mysterious green glow.

There's something in the box.

Now, I've been dragged into the room by the webs, which obviously means I haven't been able to free myself from them yet. It also means as well as the box in this room, there's also something else (that did the dragging), although I can't see anything untoward in this room (apart from the odd glowing box on the sofa). It's also eerily quiet and icy, icy cold. Oh, no, there's a clock ticking somewhere, that really enhances the eerie quietness. 

And yes, there had to be. A shuffling sound from behind the sofa.