The third key smoothly turns the lock, and you quietly open the door. The moonlight gives dim illumination to the room, and you can see stuff piled on the bed. There's a oil lamp next to the bed, but it's not lit. You slip on into the room, but a search of the table produces no matches or other means to light the lamp. Oh bother! How's one to snoop properly, without any reasonable light?
"Think I'll go get a match, or a lit lamp"
"Who, me? Are you kidding, I'm a mage (sort of...). I'll use my Ignite Fire spell to light this sucker!" Your skill with this spell is an 11. Remember, a critical failure causes a backfire (B146 &147) and costs 4 fatigue. A success also costs 4 fatigue, per the "mage gift" rule at the adventure's beginning (note the fatigue on your character sheet), and lights the lamp.
A normal failure costs you fatigue, per (B146 &147). You may try to light the lamp as many times as you have fatigue for. Note that if your fatigue gets to zero, the excess points go against your Health, and you collapse on the floor unconscious!
"Fainting in the middle of espionage is fun! I exhausted all my fatigue (and maybe then some), but I wouldn't let that darn old lamp get the best of me!"
"OK, I've got a lit lamp now, so what do I see?"