"It’s like when a kid gets in trouble with water they become almost invisible… it’s very strange."
Well, it can be hard distingishing kids playing in water loudly and just ordinary play screaming - and kids panicking in water. It looks and sounds the same on first glance in many instances. Or rather not. When they are loud, they still have energy and their head well above the water. (you cannot shout so well, with water in your mouth)
The scary part is, when they reached their limits and do not have the energy to panic anymore and just fade and drown.
If that happens, it is very important to not panic yourself, go in quickly (but not headless) and maybe know some CPR basics if necessary.
There are cases, where the drowned child got rescued, but the paniqued parent drowned dead. Or the other sibling.
(not in pool, but in river/sea type scenarios)
But better avoid that alltogether by paying attention before and choose the site accordingly. I mean I am also very often with my toddler at a river, where he can play at a shallow spot. I know it is dangerous if I stop paying attention to him, because the river has a strong current and rocks in it. And he already knows the dangers, but he overestimates himself quickly. He is the kid. I have the responsibility.