Wait.....How do you identify pre snap a DB coming on a delayed stunt? If you identify him as a potential rusher, isn't everyone a potential rusher? This OL struggles enough with the man directly in front of them. Now we want to complicate the matter by telling them that either safety might be a potential rusher?
Basically Vaccaro was the "MLB" in that defensive set ... This had to be a failure pre snap , they overlooked him being a DB instead of being "The Mike" and didn't make the right protection call .... Again , you can see Fulton recognize it but Martin didn't.
Yes , Martin has had a few plays where he's helping when he should be blocking someone else instead .... Delay's and stunts kill this bunch.
I recall a free rusher right up the middle on a delay not too long ago.
I don't recall if it was a similar situation with a nickel / dime package with the rusher being a safety or if it was a base defense LBer ... but Martin was the individual who had to make the critical decision.
Edit - the play you posted was the one I was thinking of .... Chiefs LBer Dorian O'Daniel #44.