In your first three posts mentioning the colleague you say the pool was left unattended.
"pool left unguarded with kids in as a colleague refused to lifeguard"
"He refused to go onto poolside"
"I left because you cannot stay for longer than 1.5 hrs. It’s hot and sticky, 1 hr is a normal shift, no longer than 1.5 hrs. Colleague came to check and returned to reception without staying."
This changes then to say you left because your colleague had replaced you. Though, although you'd left, you knew he had also left shortly after. (That was your moment to report a serious breach of safety regulations btw, not Monday when I next saw my manager
I left because he was there.
he ambled back after I had left. It has nothing to do with me
"Water testing.
support came. I left. Support left after me"
Here water testing person arrives and if I've understood, seems to be a different person to the colleague, as you'd already said in your earlier posts that your lifeguard colleague was refusing to come poolside. Or has come, then gone. Or something. Ambling.
"He refused to but someone had to take the water tests. I said my time is up I need to be rotated. Water testing is also a legal requirement."
"I took my chance and left when he came."
Unclear here if "he" is water tester or colleague, or, given what you said earlier, they're the same person. Don't think they can be though as your replacement colleague had already made it clear they weren't coming poolside, hadn't they?
"Pool responders and lifeguards test water. My colleague is the one who was due to rotate me. He did and I left. It’s not my fault he left poolside after that. "
And here, the colleague does replace you after all.
I do agree that you'll need to work on your timeline.
I'm off to work now, where I'm responsible for lots of children who won't be left alone at any point.