What happens when you go in the Velvet Room? Does time function differently in the Velvet Room? [Persona 3,4,5, and Q MILD SPOILER]

Your friends don't know the existence of the Velvet Room, but wouldn't that alarm somebody when the MC sudden disappears and reappears? I can't imagine your friends waiting for hours for you to fuse personas lol. In Persona 3 and 5, your friends asks "Why are you spacing out?", while in Persona 4 no one really said anything in the TV world. In Persona Q, the P3 cast were saying along the lines of "how long is the MC was going to be in the Velvet Room?".

I'm guessing your friends don't say anything because the MC told them at some point and they got use to it? And maybe it's not hours, but a few seconds or minutes in the Velvet Room?