Am I crazy for being angry at this?

The other day I was on a roller warehouse ladder.

I was about 180cm/5'11" from the ground.

All my attention was on the inventory at the warehouse where I work.

A coworker thought it would be funny to gently shake the ladder. It was almost nothing but I still got a instant little heart attack. A curious toddler probably could've shaken it with as much force as she did.

I look down in distress and see her looking up with a little Smirk on her face and two fingers on the ladder.

On a normal non-working day I've felt light earthquakes and I felt slightly distressed. Idk if this happens to everyone who has felt the ground move.

But here I was nearly my height above the ground so my distress was way stronger.

Am I reasonable for thinking that what she did was fucked up