Su Shi added a sentence: "We lack transportation."
Lin Wu's disciple, Lin Meng said: "Then we'll just steal it, why not use this opportunity?" We don't have transportation, but Nightmare does.
Tactically speaking, Nightmare generally wouldn't deploy drones to patrol their controlled territory often. After our team infiltrates the Nightmare's area, using drones for surveillance gives us a great chance to catch Nightmare off guard.
Maya isn't afraid of Nightmare's retaliation. With Nightmare's character, if they knew Shadow was at the railway bridge, even if you don't attack them, they would come at you anyway. However, there is also the possibility that Nightmare might just move their base, especially considering they have never won against Shadow, particularly Lin Wu.
Thus, in a sense, Nightmare sees Shadow and Lin Wu as enemies, but Shadow and Lin Wu have never regarded Nightmare as an enemy. This results in them initiating an unprovoked attack.
