Matty:

"...while your constant improvising is impressive, I'm not a big fan of making up as you go along."

+"...from now on things will be different."_

"Look, they say that it is better to be lucky than it is to be good. but in my experience anyone who has ever said that has wound up dead. So far I think you've been really lucky."

"But I need you to either play by my rules, or prove me wrong. Show me that your way works and won't get you killed, I'll back off. But mess up even one time and the word "improvise" falls out of your vocabulary."

So, one mistake and he should play by her rules and get in touch with her every time to ask what to do next, even when there's, as usual, only a split second left to decide? That will get him killed even faster than not being lucky.