You look at the water. It’s going to be cold. May be you should ring someone first. The fire brigade? Metcalf? Davy would have woken up, wouldn’t he, as soon as he started getting wet? And there’s all the junction boxes down there. The water itself could be live. Davy will be fine: he would have got out by himself. And if he hasn’t… you can simply deny all knowledge of him being there earlier.
That’s not like you. You feel your stomach twist at the thought of it. As far as you know, there’s a man in the basement, probably insensible with drink, about two foot of standing water, and you locked the stairwell door.