Interestingly, the one door switch already saved the day when we were taking off and the audible warning came on. On the 900X panel, a small warning light comes on the PFD if the door switch isn't contacted. At a higher speed an audible warning chime starts.
We often taxi with the door held partially open for cooling, so I'm used to seeing the warning light. Just before takeoff we close the doors, then I look over at the MFD to check the engine instruments for "gages green". I went to full throttle and was rolling down the runway when the warning chime started.
I checked my engine instruments first, then checked my door handle was down (at the time I didn't know that there were no switches on my door). Then I looked over at my wife's door handle and verified it was down. Then I noticed a thin strip of daylight at the bottom of her door...... The front pin was in but not the back. There is no center latch on my -10.
By that time the nose was starting to get light and the runway (2713' long) was getting close to half way used up. I pulled the throttle and was able to stop without too much stress. Now I not only verify that handles are down but the lights are out too. So now I'm thinking that it would be a good thing to install the other switches....