For each object misunderstanding

Hello! i have a misunderstanding about “for each object”.
Condition :
“repeat for each object of object”,
-----“Object” is in collision with “minus”,
-----“trigger once”
action:
" object.variable(value) - 10."
My problem - i have three objects, when one of them is in collision with minus, this code doesn’t work for two another objects.
I thought that “repeat for each object” would solve this problem, but i was mistaken.Help me to understand “for each object” and to make my code right.

Here’s a link to a thread that covers this, with a work around too.

Thanks! It made some help.