
I just watched this movie tonight. Hadn't seen it in about 20 years.
I'm glad to see other people already caught this one. It is hard to determine which sak she is using. It definitely looks like a 91mm SAK with at least 3 or 4 layers.
After saving Christian Slater, she kills a guy with the knife blade but she is hand cuffed to the banister of the stairs in her house and left to drown. (the water is rising very quickly) So she then uses the screwdriver once again to unscrew the banister one section at a time, thus allowing her to slide the cuffs up the banister and out of the rising water. At the top of the stairs she is stuck and unable to go any further. This gives Slater another chance to rescue the resourceful heroine. Although it is not clearly shown, this would imply that her SAK does not have a wood saw. So my guess is that it was probably a Climber.
couldn't find a picture but this was the scene