The RB motions to empty and the Panthers run an overload to the defensive left side. The rush sends two through the B gap.
End - Contain
Tackle - 3 Tech, Long Stick to Opposite A
Tackle - 3 Tech, Work to Contain
Will - Rush B gap to A Gap
Safety - Rush widest part of B gap
Mike & Nickel - 2 droppers
End - 3 dropper
Corners - 1/3
Safety - MOF
The Panthers rush 5 against a 5 man pass protection scheme. The offense has enough blockers but the rush scheme violates the rules of the protection.
Initially the Guard and Tackle are forced to set to the right to block the DT and DE. That leaves 3 blockers to the left (Center, Guard, Tackle) to block 4 rushers (DE, DT, Will, and Safety).
The offense could pick up the rush if the OL was sliding to the pressure.
The offense doesn't know the End is going to drop off into coverage. Therefore it is impractical for the offense to slide to the pressure and risk leaving a DL unblocked.
If the OL slid when the Panthers were rushing 4 down linemen, the DT and DE would have an easy 2 on 1 vs. the RT.
The RG initially set to the DT. Once the DT worked outside to contain, the guard was able to redirect and block the long stick DT from the pressure side. Once the RG redirected the offense had 4 blockers for 4 rushers. The challenge for the offense is the Center has to travel back with the long stick DT. The Center set to the pressure initially and has no way of knowing the End opposite the pressure dropped into coverage. If the Center let the long stick DT cross his face, there is no guarantee the guard will be there to help. Pre-snap the protection rules are the RG and RT need to block the DT and DE. The Center has no way to know that is no longer true. Once the Center traveled back the defense created a 2 on 1 for the LG. The guard is also forced to travel back with the Will. The LG has Center help allowing him to pass the long stick DT to the Center. The Will rushes the B gap and the guard sets to him. Once the Will makes an inside move; the guard is forced to travel back with him. The guard can pass 1 inside move to the center, he cannot pass 2 inside rushers. That leaves the safety rushing from the secondary on a clean run through for the sack.
This pressure is a good reminder about the nature of bringing pressure. There is a balance between coverage and pass rush. The more coverage the more time the rush has to get home. The more pressure the less time the coverage needs to cover. Some coaches are tentative about dropping a DE into coverage, thinking he will be a major coverage liability. The expectation of the DE as a pass rusher sets the OL's protection rules. Dropping the DE into coverage allows for an overload rush that attacks those protection rules. While 3 under 3 deep zone coverage is not perfect, dropping a DE does allow for overload pressures that can cover up those imperfections.