I don't see Dana White being involved. Brock Lesnar is not his whole business. He has a lot more at stake than one big pay-day. He has fighters in every category that make him money and credibility as real athletes is the key. I think he wants to keep MMA as far from WWE as possible.
Now, if Brock thinks he done, he (Brock) may take the WWE payoff. In this case, Undertaker did a friendly thing, offering him an out.
IMO, if it was staged, well, that's show biz. No harm. It may have been, by Undertaker/McMahon. Undertaker is a shitty actor though and couldn't concentrate on his interview because he was waiting for Brock to come his way...coincidentally. And he looked like he felt bad about the outcome. As if he likes Brock. He didn't say one thing about him losing, being beaten, humiliated or anything. If he hated Brock, he'd talk shit. And it didn't look spontaneous at all. His wife even looked like she knew it was coming. If he really wanted to rub it in, not for wrestling, he would have said something like "Nice work, Buddy" or "Oh, really got your ass kicked, eh Champ?" other such taunting stuff.
Even in Brock's weakened condition, he'd eat The Undertaker for lunch in a real fight. He's a real wrestler and fighter, ass-kicking or not. I think he'll be back. If you followed his college career, the guy is a fantastic athlete, not some friggin' Bob Sapp. And if I recall, there's already an urban legend about Kurt Angle handing the Undertaker his ass on a plane flight after exchanging words. No contest.