8-directional movement seizures

I'm working on a top-down 2.5D roguelike. I've got an issue with my 8-directional movement cod3.

This seems like a pretty common issue, my WASD controls and arrow keys work perfectly fine in all 8 directions, but if you happen to not be top quick in switching directions and have 3 buttons pressed at the same time, the player will just try to switch between all 3 directions ar once. It'll just freeze in place and swap directions rapidly like it's having a seizure...

How can I have the game read only the last 2 inputs that were entered? Or is there something else I can do that would work better?