@Shellshocked2018_ No such thing as a silly question!
As the chemo passes through your body, some of it comes out in your urine. These are highly toxic substances. You'll see the nurses wear thick protective gloves, glasses and gowns to handle it. You don't want anyone except yourself anywhere near the stuff. Almost all loos splash/spray when flushed. So keep the lid down and no drips! It's also why they tell you to use a condom if you have sex during chemo.
My husband and I still used the same loo but I was very very careful. K xox