You underestimate the ability of the mind to block out pain under extreme circumstances...and overestimate the effectiveness of a strike to the groin. I have seen case studies about people who have gone so far over the edge that they inflict extreme genital mutilation. You look at the anatomy of the male genetalia...the glans tends to be very sensitive, there is a large dorsal vein on the underbelly of the shaft...which is far less sensitive to pain, and the testicles...which are also very sensitive. The balls are a harder target then the whole front area, there is a great chance of missing or glancing the target, and grabing the balls is pretty hard to do through jeans or pants.
Despite this...people can take a whole hell of alot of pain under the right amount of duress...or excitement. If somebody is really jaded, and used to extreme pressure or pain to that area, they might even enjoy coming close to the area where irreperable damage is done. If you don't believe me...I could post several links to fetish sites, and fem dom shit...but it would seriously jeapordize my membership to this forum.
What I will post this; stun gun to the nuts...and getting up within 45 seconds or just running around in pain. Certainly not the 5 minutes you propose. And perhaps something you could fight through in the right circumstances.
stun gun to the balls
http://www.youtube.com/watch?v=9jvA4yMKde8
http://www.youtube.com/watch?v=q9vag4ziPU4