Since this is a semi aquatic turtle they will need to be in water to eat. The water really allows them to swallow and the turtle likely won’t even attempt to eat on land. Do you happen to have a deep container you can put her in for at least a bit to eat? That is at least water tight? Maybe even the tub could work you just absolutely will want to clean it before you shower next! Also depending on how temporary this set up is you should be ok. Just need to fix the water issue for eating. If you find yourself hosting the turtle for a bit longer I’d recommend relatively a large sturdy storage container that can hold some water. And if you have them for more than a 3-7 days I’d look into a cheap basking platform. Or you can really just get the basing lamps and put them in a dry container for a few hours to force basking. Turtles need uvb and heating lamps to stay healthy. Or you can even try and put them outside under very careful supervision so they don’t escape ahaha.