We're behind in the race, but we have a great anchor. We can afford to make bold moves. Bringing two down threatens to do serious damage to our opponent. If he escapes or hits, we're no worse off. But if he fails to hit or escape we're positioned to clobber him.
Bring down two - only 7 shakes hit for our opponent, but many many more are devastating for our side. And we can recover quite nicely from a hit.