So you are comparing the best UFC fighter at the time vs a complete nobody boxer vs Tyson vs ANY UFC fighter? C'mon....... 
I can tell you based on personal experience and eye witness account that Royce was by far NOT the best Gracie let alone the best fighter representing Jiu-Jitsu at the time. As far as the brothers that were living and teaching in Cali at the time, as well as their cousins the Machados, Royce would have been ranked dead last. He was chosen by Rorion by default. Royler, who was better than Royce, was considered too small (about 135 lbs) and his English was practically non existent at the time. Royce, was Rorion's right hand man at the time as he brought him out to America when he was just 18 to help with teaching and was more like a son to Rorion than a brother due to the huge difference in age. Rickson, easily the family champion who would literally toy with Royce, would not have been so easily controlled by Rorion.
When Rorion asked his cousins, the Machado's, specifically Rigan and Jean-Jacques, to help Royce train for his fight with Kerr, and this was when Royce was already a season fighter and considered one of the best in the world, both Rigan and Jean-Jacques, who I was training with at time, mentioned how surprised they were at the low level of Royce's Jiu-Jitsu. When I asked if he wasn't a Gracie but just one of the members of their academy how would they rank him. Rigan said he would consider him a high level purple belt. So, that boxer is at a far more higher level in his discipline than Royce was in his. That boxer was rated in the top ten and I doubt Royce would have even placed as a Black Belt in a major tournament considering how easily he got choked unconscious by Wallid Ismael when Royce was already a famous UFC champ.
That guy you see being introduced at .29 sec is Carlson Gracie, son of the founder of Gracie Jiu-Jitsu, Carlos Gracie. Carlos was also the older brother of Helio, Rorion's father. Wallid is from Carlson's school. A bit, if not a lot, of bad blood between those two camps. Carlson comes from that generation of Vale Tudo fighters where there were no rules, no time limits and no weight classes. Compared to how they competed in those days makes today's UFC seem like child's play. Carlson was also was the one who avenged Helio's lost (Helio was 43 at the time) to his former student, Valdemar Santana, after going at it for around 3 hours and 45 minutes straight! When they say no time limits in Vale Tudo they mean it!
Royce vs. Wallid
http://www.dailymotion.com/video/x27qoe_rare-royce-gracie-vs-wallid-ismail_sport