In need of a creative solution

[GraphicsKid]

So let me set the stage here: so you're in a flooded basement, and there's a staircase that goes one level lower. You're on the upper level and you're already up to your knees in water! So obviously the downstairs is kind of off limits, seeing as how it's underwater. SO... if the player is brave enough to submerge themselves and try to progress this way, their only reward shall be a locked door... if you can call that a reward. So no going down, so what now? Well the player is supposed to toss boxes over the water to form makeshift platforms to hop from to reach a balcony that is at the same level as the floor, but above the staircase.

Here's the problem: All the while you're building this box bridge to get across, there's a grunt patrolling the cellar (and he's not just going to disappear, nor alert you to his presence by blasting creepy music!)

Only problem is, the monster doesn't really handle the water that well... At least with the player I can add movement resistance and reduced gravity. The monster, if he sees you perched on top of a box, he'll run right at you... down the stairs... and start swatting at the water below the box, below you!

Does anybody have any suggestions for a better way to handle this?