There are two different TIV's (this guy and bushrag), so I could be getting them confused...but here are my observations from 2005.
Of all the times I saw them last year, there were two distinct major tornado days in the first half of July with tubes dropping everywhere (6/7 in KS and 6/12 in W TX). He was miles away from the tornadoes and not in any hurry to try and intercept them...staying off at a safe distance. Heck, I could have drove into the tornadoes several times easily myself with little effort.
On 5/31 in the TX PH, a very slow moving tornadic supercell was rampaging near Dimmit and Hereford again offering AMPLE opportunity to waltz right into the bear's cage. I saw this guy racing the opposite direction away from the potential tornadic circulation while I'm driving towards it.
So, in my mind from what I've personally seen, they don't seem very eager to drive into tornadoes....but love the publicity surrounding them. Has anybody yet seen any video footage from these guys getting into a tornado? I certainly haven't. If anybody has, then I'd like to know. They've been doing this for a few years now, so you'd think there would at least be one piece of video out there somewhere.