I don't think he would've been that ashamed,as the shooter himself says he and 2pac had a struggle for the gun,thats not quite the same as shooting yourself. You can only not like the fact he went at Biggie if you don't think he really had a reason for being mad at Biggie. Who Shot Ya alone was one reason to be upset,along with Biggies percieved lack of loyalty which is subjective. But Pac wasn't completley off when he said he was hearing Biggies homeboys shot him. Dexter Issac later said he was Biggies friend in his confession.
The fact you think he "Went too hard" at Biggie is just you speaking from a bias standpoint as a Biggie fan possibly. If Hitemup is too hard,what is a song like No Vaseline considered lol. Whats overkill and whats not is also subjective I guess. We forget Pac wasn't on DR that long,did he really go hard at Biggie for long?outside of a couple of diss records,main record being Hitemup? The hype and humiliation surrounding that song doesn't really equal Pac going hard or beating a dead horse. He had moved on to Jimmy Henchmen by the time he started recording Don Killuminati ,and begin to downplay his beef with Biggie in the media. So maybe he did realize Biggies involvment wasn't as deep as what he originally thought it was,and was just in too deep to take it back. But when he's sending letters to Madonna asking for information on Jack and Henchmen,sending threats to persons like Jimmy and Jack,as well as their loved ones on Don Killimunati,is that not asking for smoke?
If 2pac didn't get killed in Vegas,do you believe no smoke would've come from Against All Odds?if the answer is yes,you cant say he didn't ask for smoke,he practically begged for it at that point sadly. Its crazy to think had he not been shot in Vegas,he wouldv'e been marked for death on both coast.