"This means that the player(s) can not inflict pain, damage or harm anything. This includes inanimate objects.
Remember that this only limits things the player has control over."
My take on this would be... Trying not to get harmed by enemies, let the enemies crossfire and kill eachother off or smt.
Now to take you on point. placing a mine would be attempting to harm enemies. Smells a bit fishy. it's not immidiately harming enemies, but still the player is directly attempting to inflict damage. Throwing some cup or box at the enemies head would also be too direct. placing a camouflage blanket on top of a pit with spikes and watching enemies fall into it... now there, the player just hides the scary deadly stuff... that's would be a fun tangent on the limitation.