A little after midnight on Thursday, a group of young men arrived at 40-year-old dentist Pankaj Narang's house in west Delhi's Vikaspuri, dragged him out on the road and beat him with hockey sticks, bats and rods till he died, after an earlier disagreement. Delhi Police data shows that one in five murders are unplanned and committed within moments of an altercation. Is the capital a city on a short fuse?