A carboniferous swamp is one of the most dangerous places you could hope to be in. If we're assuming I have the materials to and know how to fix my time machine, I'd start doing that as soon as possible, while finding high ground to spend my time because the only threats would be giant insects and mosquitoes and stuff. Then I'd try my best to get out...
^^there's a big problem though, the oxygen-rich atmosphere of the Carboniferous makes the forests very susceptible to wildfires from massive storms. You'll probably get zapped sitting on a tall tree or smth
