High-rise window washing.
Mid-spray during an episode of explosive diarrhoea.
I would think that the worst would be any ground vehicle (not made to fly) that was going very fast like a car or train. If it happened to be going up hill when gravity stopped, it would launch itself off the ground and momentum would keep it going for 10 seconds. That vehicle would probably get pretty far off the ground before gravity kicked back in. Then it would crash back to earth, probably killing everyone on board as well as causing mayhem to whatever it landed on.
you know how people stand too close to volcanoes? – yeah… that!
Batting at a baseball game, the ball would not lose momentum from when it left the hand