I suspect 10000' is a little bit too much time to overthink the situation!
Most cases over land yes and its probably the last 1000 feet where it counts
There are exceptions over water where you may just glide to land or a distant passing ship and have more time to get your position fixed and communicate.
Maybe at night where you might just make within the boundaries of an airfield
Over a City or dense forested areas where you need to glide clear and of course over mountains.
Other than that I remember flying the Seneca at FL210 on one trip Spain UK and getting a groundspeed of just under 300 KTS most of the way
I could have made Malaga UK in just about one but dropped into Jersey being cautious
other than that normally FL100 to 120 to try and stay in airways in twins off oxygen and higher if weather dictates
Pace