how to avoid putting the whole team on tilt

A simpler option is to be a decent human being and not harass teammates after every single mistake.

If the team goes on tilt because two of them are duo queueing? That's the team's fault, and they need to fix that attitude.

so fucking tru. someone was flaming at me then his duo told me "sorry he needed to take a chill pill, he was just, you know... playing bad" We were really behind and I had hope but after knowing that there was a duo in our team I immediately surrendered.