If you look at the long ends of the switch where they push through the plastic crib, you'll see a tab on both ends, one will be longer than the other. Use something skinny but sturdy like a paring knife and pry gently on the long end (usually towards the top of the panel) while also pressing on the switch. It'll just lever out.

Did you have the switches out to swap driver/passenger in your test above? Can you elaborate on what you did and what the results were?

__________________
Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]