I don't think any lanes were closing in this scenario at all
It reads more like the hard shoulder was coned off and a 50mph limit was imposed. Either way it would be a scenario where more caution is required. Without sounding judgemental but any time I have a car on my 4 o’clock or 8 o’clock blind spots, I either speed up or slow down until I can see them. I certainly wouldn’t like them being in my blind spot for two minutes.