This customer is extremely rude and expects instant service

I work at a gas station. This lady expects instant service, where she wants me to drop what I’m doing instantly and serve her. The problem here is that postponing what I’m doing can be a HUGE hazard. For example, I could be cleaning a gasoline spill, and she wants me to stop what I’m doing and serve her. Sure, the area may be coned off, but someone COULD run over the cones and cause the spill to ignite due to their exhaust. I want to refuse service to her. This customer is the same one that complained over the $100 bill policy (the first post I made about this).