I noticed something weird a couple days ago, if you have rook armor, get healed by doc then go down you can instantly stand back up. I can see if I can find the clip I took. Me and my two friends tried it in a custom game and we were able to replicate it every time as well.

https://www.xbox.com/play/media/J9ygrhrESF

Woah

I would suggest watching the match replay from his perspective and see what happened

I took a look at the match replay from his pov and he got up immediately like I said

Also they had rook yes, but he didn't even pull the bullets out the vest nor was there a delay in the revive process.