1. Does it block light from outside?
Yes, the silver-coated surface reflects and absorbs sunlight to block up to 98% of the sun’s harmful ultraviolet ray. This comes with a rain fly that will also keep the direct sun from shining in the top. The door and the window can zip shut too. So this will block all direct sun.
2. Is this fire retardant?
No, this is not fire retardant, but it was made with high-quality, waterproof taffeta 191-D nylon polyester and flexible steel for durability.
3. Will it need to be anchored if indoors?
Depends on what you are going to use it for. It's very light and will stand on its own. If you are worried, you can also put some weights inside in the corners.
4. Does it have a floor to protect feet from the dirt while showering?
Yes, the bottom mat is attached to keep you away from the dirty ground and ensure the cleanliness. Water can also flow from the mesh corners when showering.
5. What are the interior dimensions of this tent? Width and height?
It expands to the size of 47.24" x 47.24" x 78.74" in when set up. Much taller than any other tents in the market.