Doc was absolutely fearless...this is what made him so dangerous. He was willing to put his life on the line at any time, against anybody, anywhere. Probably the main reason he was fearless was that he was dying...he had the consumption (tuberculosis) probably didn't want to die in a hospital lying in a bed but would rather die with his boots on, going out in a blaze of glory. (J 10 suited against 3 other players preflop) Anyway, this is what made him FEARLESS. People usually gave him a wide path, sensing his death wish, not wanting to mix it up with him, given the stakes were so high. (Going all in close to the money or in the money and going for the top payouts in a tournament is a deadly weapon...most good players will throw away A10's, AJ's, 77,88, 99, fearing a bigger hand, like AK, QQ, KK, AA, and will give you a wide path when you go all in...if you have a pair of 2's, or A3, or KQ, and a few player limp in, with on the button...or after the flop, it gets checked around, but the last player bets the pot..., or the pot gets raised and 2 calls, and you have QQ...and everyone's on the bubble, go all in...see what FEARLESSNESS does for you...the Meek don't inherit the goods in poker)
There are many times in the Old West when a gunslinger had to be fearless and be willing to put it all on the line. (thus, all in , in NL poker) Most average people of those times were afraid, and rightfully so, or too timid to do this, so they never reached the top...most of the best, have this fearless attitude. You gotta be willing to put everything on the line, in order to reach the top.
Poor Doc, he was so good and fearless, that rarely did anyone challenge him...and so he DID end up dying in a hospital bed, with his boots off...up in Colorado in a little make shift hospital in Glenwood Springs. (Wyatt - "how are you today, Doc?" Doc - "I'm dying...how are you?" )