HELP! A maxi mini just commit suicide in a PH. What do I do?

[SanguinesDream]

I woke up to an awful noise of juddering to find that a maxi mini somehow made its way up to a powerhead in my QT tank. #$&%#$@*£^@!!!!

I have a vicious head cold and my faculties are not with me ( plus I was interrupted from a dream where I was a samurai fighting a ceremonial dragon come to life) so I quickly unplugged the powerhead and removed it, tore open a handy super activated carbon filter and jammed that in my filter to try to save the other inhabitants from the chemical warfare, what else should I do?

I just did a 50% water change the night before last and I don't have any premade. Should I give the carbon an opportunity to work or change the water and if so how much?