I got this combat report (literally as quoted):
"it The Pump Operator in the body part, but the attack is deflected by The Pump Operator's (cow leather cloak)!"
This in fact happened to both my pump operators at once, after they had been uneventfully pumping for several days. My best theory is that the layout of the pumps allowed for a rare freak wave to wash back (through a diagonal gap) and dislodge one pump operator, and then with extreme bad luck enough of the wave moved onto the tile occupied by the other pump operator to dislodge him as well, leaving them both drowning because there was nobody else to pump the water away. Presumably there was a constant trickle through that diagonal gap all the time they had been pumping, but usually too small to have any effect.
The room was set up like this:
X#PP#
#PP#X
Where # is empty space, X is stairs and and P is part of a pump, with both pumps pumping east.
They escaped from the watery pit quickly enough, after drowning only briefly.
I was just a bit baffled by the message, particularly the blank double space where a verb should be, and the non-specific attack on "the body part". Besides, in that other fine ascii-based game, Angband, when "it hits you" that means you're being attacked by an invisible monster, usually Smeagol, so at first I feared there was an intruder.
One of them has bruised his hand. This will get better by itself without a hospital, right? (I don't know what a doctor could do about a bruise anyway, but this game is pretty perverse and for all I know it's going to go gangrenous or undead without token medical attention and a month's bed rest.)