Who knows. Maybe it will show it as a flash back of how he got out or he may have even left before she got back to her room and they lead viewers into thinking he was still in there.
Yes, I think that's right tigger, we were all just lead to believe he was still in but he'd already left.
Or, when Stella was cleaning up the other detectives nose in the bathroom after she thumped him and made it bleed, Spector could have sneaked out.
It can only be brilliant if it's believable. If there's no explanation of how he got out of the hotel room, then it holes the drama below the waterline.
I reckon he heard her key in the door and hid in the wardrobe ,there was a shot that looked as if he was peering at her through the gap in the door .She was just about to open the wardrobe when Burns showed up.They had the row ,she clumped him one ,then she took him into the bathroom to clean up and Spector took the opportunity to leg it .