Sabotage 7 Schnottz Powder Kegs.
It is good to have friends, <class>! While kindness is its own reward, there can be tangible benefits too!
Some friends of mine recently intercepted a shipment of Schnottz's plunder and found something that should serve your needs nicely.
It's a piece of titan technology that renders the user nearly invisible. If you use it in the enemy camp, you might be able to rewire their explosives and make a mess of their operation.
Each charge has a limited duration, so don't stray too far from safety!