I wish he had. Part of me still hates Pedro a little for not doing that, but as someone else said, ultimately it's Grady's call.
I think Timlin had given up one single in the postseason to that point. And not in 0.2 IP either -- he was so lights out at that point that they should have called him The Generator. As in, "When they break out The Generator, you know the lights must be out." Or perhaps an even cooler nickname could be found.
Williamson was doing pretty well himself. Timlin + Williamson + 3 run lead = as close to a sure thing as exists in baseball.
Just for the record, count me as another person who distinctly remembers nearly having an excretory anomaly when Pedro came out for the 8th.