Although following this logic out, eventually you would be scoring runs without throwing a pitch!Either way it is interesting to see what the break point is but then how quickly runs compared to the number of pitches and how it adds up after the initial run is scored.
One question that comes to mind is if pitching (or offense) is extremely efficient or inefficient in one inning does it effect the next inning? Note the graph below shows pitches in inning x (y-axis) followed by pitches thrown in inning x+1 (x-axis). This is independent of pitcher, so some of the data below could be one pitcher followed by a different pitcher in the following inning. Also it should be noted that 70% of all inning x was between 9 - 20 pitches and in inning x+1 70% was between 8 - 19 pitches. And thus this overlap (meaning inning x had a pitch between 9 - 20 followed by an inning x+1 of between 8 - 19) accounts for 49% of the back to back innings.
Just one other point and that would be that in 3622 of 7708 instances inning x was less than inning x+1 meaning that generally less pitches are thrown in inning X+1 (53% vs 47%). My guess is that with additional data and data that includes other teams that this number would generally get closer to 50/50 and that generally inning x and inning x+1 are independent. Just for kicks in 2010, Jimenez had 92 instances (out of 194) where he threw more pitches after inning x. It would seem in 2010 he seemed to throw less in inning x+1 then inning x.