How to open up?

The machine will run through its brewing cycle but water will not leave the reservoir. Initially I thought this was an issue with the reservoir valve, but it runs through the cleaning cycle. With the cleaning cycle, the water in the carafe is cold. I suspect I need to replace a heating element, but I cannot access it. I used a T10 security screwdriver to remove the bottom plate, but there is another layer of plastic (see picture attached). How do I remove that? There are a couple of plastic tabs that I unclipped, but something else is holding it down - is there a hidden screw I'm missing?