[metroschultz]

The S10 trans is a toploader (The gearshift goes into the trans from the top and there is no external linkage to bind up)
The selector for reverse is also the selector for 5th.
when you pull into reverse you are moving a lever all by itself in the side of the trans. moving a gear (not a synchro) on a counter shaft.
To go to 1st from there you are moving across two open dogs and pushing a rod backward (yeah it seems different) for the 1st gear synchro and fork.
It is possible to get between the dogs and push 1st and 3rd at the same time but usually that creates too much resistance on your shifter so you will pull back and try again. If you did get 1st and 3rd at the same time the car would
TOTALLY
be locked and immovable. If this happens again you may have a problem that needs attention.
But I am going with the frozen brakes theory.
If you hit 2 gears at once. 1 time, it will happen again and again and again and again and again.......