It happens in the marksmanship challenge and it's a cheat, so I'll put the spoiler tags:
When I was wielding a combat knife this hell knight didn't hit back in melee (haven't tried if it happens with other non-gun weapons and monsters):
This is not a weapon worthy of a marksman, isn't it? You miss the hell knight.
This is not a weapon worthy of a marksman, isn't it? You miss the hell knight.
You wear/wield : a modified pistol (2d4) [3/8] (B1) The hell knight hits you. The hell knight hits you.
You hit the hell knight. The hell knight hits you.
You wear/wield : a combat knife (2d5) The hell knight hits you.
This is not a weapon worthy of a marksman, isn't it? You hit the hell knight.
This is not a weapon worthy of a marksman, isn't it? You hit the hell knight.
This is not a weapon worthy of a marksman, isn't it? You miss the hell knight.
This is not a weapon worthy of a marksman, isn't it? You hit the hell knight.
This is not a weapon worthy of a marksman, isn't it? You hit the hell knight.
(....)
This was in v0.9.9 in Linux, in the Halls of Carnage
Btw, music doesn't work in Linux (.mid files). Sound works fine.