I am confused. You wrote “…millis delay…” but millis() and delay(…) are two different things.
Furthermore, you didn’t explain what it is that you want to have happen after 5 minutes.
I can’t help this way, and I don’t know if anyone else will help until:
(1) ALL of the code is posted, not just a snippet, AND
(2) The code is formatted using CTRL-T in the IDE, AND
(3) The code is properly posted using the </> button, AND
(4) You explain what you REALLY want to do.
By the way, delay(…) is evil and should be avoided for most things, especially when it comes to a five minute delay.
All variables used with millis() should be declared as unsigned long, and only subtraction should be used.
(A) When something interesting happens, save the current time using millis().
(B) Each time through loop(), check if the then-current time minus the delay time is greater than or equal to the saved time. If so, do whatever.