After the mishaps surrounding run 3, I did decide to do it again. Got through it. My legs feel fine but I'm not sure how I'll get on with the longer runs as I'm really breathless after 60 seconds. It's not very surprising as I stopped smoking 2 months ago after 30 years regular puffing. Hopefully, it will get better with training.
On the upside, I did throw any expensive electrical items down the loo this time