Can Someone Please Explain Something to Me?

I've been playing league for 2 years now, and I have yet to understand as to why I cannot dodge during my series without my series ending. Like I was in my series for plat 4 last game and I had a yas who said he was gonna troll. No one dodges, I cant dodge, we get in game and he proceeds to feed, build sword of the occult, zhonyas, following with static shiv. If the reason I cant dodge is because im afraid there might be X opponent on the team that I don't wanna face then how come I can dodge a regular solo que match with the small penalty of 5 to 10 lp. It makes no sense.