I believe that Lagat's 7:37.9 is the 11th best US performance (all time). Lagat himself has only run faster than that 4 times (last time is 2 years ago).
A bunch of guys who have been Olympic finalists and medalists in the past 35 years have never run that fast (at any age) indoor. Looking at the guys that ran indoors regularly.
Guys like K. Sullivan, S. Scott, A. Webb, C. Levins, Centro... some bigger names than that, I am sure, have never run that fast indoors (or even outdoors).
To do this at age 40 is out of this world...
Would love to see that list...