After thinking about this one for awhile, I think Myers was doing what was planned all along (at least HIS role on the play)...Myers was supposed to get to the second level, and Caldwell was supposed to take the NT and shove him into the second level right behind/beside Myers as Myers explodes into the end zone.
But Caldwell doesn't get that NT cleared out very well, Myers senses it...tries to turn back around and help Caldwell, but it's too late: The NT has successfully held his ground AND log-jammed the middle to the point that the only saving grace for the Texans is our RT Butler.
Butler has two choices on the play, and I think he was going to be damned if he did and damned if he didn't no matter which LB he chose to block (because both LBs were in position to shoot the gap and stuff Tate).
Not really mentioned much is James Casey at FB who, like Myers, blows through to the weak side of our formation and gets into the second level...but the problem is that the strength or focus of the Panthers' pursuit/contain was never on our weak side (which was our left side of the OL); it was on the strong side (Owen Daniels' side on the right side of our line with Caldwell and Butler there alongside OD). So Casey's role was nullified immediately.
Does this mean that the play was supposed to go to the left side, and Tate cut it back (either by design, or by Tate's choice if a backside lane opened up for him)? Our scheme runs a lot on backside cuts or straight ahead hole-finding and hole-shooting...whichever one our RBs want to try for. This run play, IMO, is just one of those times that even if every person did what he was supposed to do on the play...the play might still have been a dud.
I call this play a wash. Yes, it can be quibbled that Myers might have left the play too early...or Caldwell didn't clear his man out enough...or that Butler didn't identify the right LB to block...but the Panthers did a good job of having their NT occupy enough of the "storm" that the Panthers LBs, led by a very instinctual Luke Kuechly (rookie, #59) flowed with the play and picked their gap to shoot (knowing the RB would flow to that same gap, too).
I like running plays that stretch the edges, such as the 1st and goal play that Tate ran to the right side of our line for a big gain. The run plays that start straight down the pipe, IMO, do not maximize our OL and RB ability to create space and abuse the mismatches that occur from it. Once a NT holds his ground on a Texans run play that starts up the middle, the LBs can flow and choose the gap(s) that open up. If the Texans' run play starts wide, there are almost unending gaps that will open and close for our RB to choose from. Just my two cents worth.