Carrera is covering for Antonio Conte as he serves his ten month ban.
"My role is to deal with a football team, even if at times one has to raise his voice," said Carrera of the half-time talk.
"Conte has great charisma and is a great Coach who fires up his men. I try to transmit that passion to the players on the field. I've been working with him for a year, so I know how he thinks and we continually exchange views.
"I left my phone on the team bus, so I haven't heard from Conte during the game and made my own decisions."