Possible Historical Inaccuracies surrounding Mir and the Chernobyl Liquidators in Episode 1

Just had a couple of questions about two bits in Episode 1 that surprised and confused me a little. I've found absolutely no mention of either in any appraisal of the programme on the internet.

First question is about the Chernboyl Biorobots/Liquidators and the following titlecard accompanying footage of them removing debris from the roof:

'They would almost certainly die from the levels of radiation they were receiving'

Hasn't this been proven to be untrue since only about 10% of the liquidators died as a result of being at Chernobyl? Maybe I've misinterpreted his intention here and he's suggesting that 'this is what they thought at the time, and the authorities were happy to just send them to their deaths'. Even so, its a little disingenuous to frame it like that.

Second question is about the claim that the Mir space station was intended to explore the solar system:

It was to be the first stage of the Soviet exploration of the whole solar system. A giant nuclear rocket would come from earth and join it and set off across the universe.

I'm no expert on the Soviet space program, but I've never heard about this, nor could I find anything online about it. Is this true?

I am very fun at parties.