Sometimes the best reaction is no reaction at all.
In this imagined 1927 stunt, Buster Keaton is surrounded by enough moving machinery to make anyone nervous.
The bridge beneath him begins rising.
A coal barge approaches.
The counterweight swings.
The deck keeps tilting.
Keaton responds only when absolutely necessary.

He steps.
He shifts his weight.
He crosses the gap.
The smokestack passes under him by inches.
The giant bridge mechanism sweeps behind his back.
Keaton never turns around to admire the near miss.
He never stares at the barge.
He never celebrates.
The audience understands how extraordinary the moment was.
Keaton behaves as though nothing worth mentioning happened.
Only after the bridge stops does he look down.
There is a drop of oil on his tie.
That finally earns his attention.
He wipes it away.
Perfect.
The joke is not only that Keaton escapes danger.
It is that he apparently never considered the danger important enough to acknowledge.