They are often available on eBay. I would place them on some newspaper or an easily cleaned surface tough to capture and pee and poops
Most newspapers are printed with soya ink now so it should be okay to use, but keep an eye on your little one and see how she reacts. I use the bath for the Roborovski as harder for them to get out from. Syrians need constant supervision wherever or whatever you have them in out of their normal enclosure. Maybe try setting up a large underbed storage tub maybe as a play box? You get some long shallow ones quite reasonably priced in homeware shops.