Run it twice

[cjmewett]

Anyone care to discuss under what circumstances they prefer to run out turn/river multiple times in an all-in situation? I know this is a reasonably basic question, but I'm curious about the range of responses.

This is prompted by a thread on M/HPNL where lapoker chooses to run the river twice with his baby flush against bottom set:

link

Here's my question, really: what does the villain have to lose from multiple runs? Half of a pot in which he's a substantial dog? Anyway, discuss.