"Sorry if I interrupt you" then go ahead
A neat simple technique for high-power, high-warmth:
Whenever you really wanna say something, or whenever you feel what you gotta say is important, go for it.
But do acknowledge that you're interrupting if someone else had started talking:
Him: yeah I had something...
You: oh yeah, BTW, (look toward him, reach out with a hand) and sorry man if I interrupt you one second, just wanted to say we should get moving as it starts in 10 minutes.
Everyone: yeah, let's go
You: yeah, sorry man, you were saying...
That way, you get your point across, without disempowering others.
Funny, I was looking at some of Brad Pitt's interviews for high-power and high-warmth, and look what he does:
Pitt: and by the way, not to hijack your story...
(finishes the story)
Sorry. You were heading somewhere (points towards Margo), I just (punches the table as if to say "I barged in")