Wright model B crash on Nova

Finally got to see this program over Thanksgiving. Very interesting
but I don't understand what happened.

The assembly went very well and the engine was installed and run and
everyone was ready for the first flight when it started raining. It
rained and rained and rained for about a week. Finally it stopped and
everyone leaped to get the Model B out and fire it up.

Needless to say, the grass runway was a mess and the pilot decided to
taxi down it a bit to try to find some non washed out area's. This is
where things got confusing to me.

I did not see the washed out areas, but I'm assuming that they were
certainly there. The pilot survived the ensuing crash and explained
that he got halfway down and the airplane was at full power and he
found the rudders much more sensitive than previous tests. He was
nearly out of control while taxiing.

He was halfway down the runway and for some reason felt he had to make
a decision about whether to takeoff or not. This is the part I don't
understand. Why did he have to takeoff or not? Couldn't he have
simply shut the engine down?

Once in the air, he found that turning was a problem: the airplane
seemed to go into nearly uncontrollable skids. He recovered from
several and then attempted once again to turn back to the airport to
land and it went into another skid and crashed into the trees.

The pilot was rescued from the airplane and the airplane was recovered
from the treetops and is being rebuilt.

But why did the pilot feel it was a takeoff or crash situation, which
is how it was presented on the show. Surely there is some way to shut
the engine off, isn't there?

Thanks, Corky Scott

PS, sorry if this has been gone over previously, I didn't see it if it
was.