The wizard's treasure chest contains a jar of No-See-Me grease, which makes the user invisible if it is rubbed on his body and equipment. The effect lasts until the grease is washed off. There are also 3 healing potions with 3 doses in each one, each dose capable of doing 2D6 points worth of healing for a single swig.
You take the magical items, grab your companions who are either dead or injured, and flee his abode, heading straight back to the intersection.