[bagels]

Hard to know whether a metal gasket would work here, but it's extremely unlikely as you need tight tolerances and high clamping force. Rubber is used here probably because those things are absent, and there is probably movement involved. Other commenter has the right idea, you can probably make a new gasket.

[vfinn]

It's hard to say what kind of forces are involved. I could probably open the side panel and be able to see if I run it without water. I was hoping the rubber seal would mostly be flapping along mildly as a whole.