I followed all the rules to a tee. Unfortunately, before immersing jars for final boiling, I apparently did not tighten the lids enough. I just took them out of the boiling water after 30 minutes and the screws lids were loose and looks like water got into jars. I understand that I can't keep them like this but if I removed them from the jars and put the slice in the refrigerator are they ok to eat within a few days?
Yes, basically anything cooked will last at least a few days in the fridge.
If you want it to safely keep it longer than that, you can freeze it. It's probably best not to try to reprocess the jars though, since you don't know exactly how much water got in (and how much acid and sugar got out), so if you're unlucky it could upset the recipe enough to make them unsafe.