Welcome to the forums drowe1010.
You should be advised that discussion of downloaded materials is a somewhat tricky area around here. We do not help with videos that are downloaded without the permission of the copyright holders. This usually means payment of some kind. Torrented files don't often meet this standard, though on rare occasions you can find movies in the public domain on torrents.
You should read through the rules of the forum regarding copyright protected material.
Now, with that explained, on to your problem. This "lagging" is probably caused by too low a bitrate in your conversion on those action sequences.
It has been a while since I last used DVDFlick, so I had to go look at the fine controls, or lack thereof in the Project Settings. The target bitrate is normally set on Auto-fit, which will compress the movie to fit your target size...whatever you size you are trying to hit. Normally you are trying to convert to fit a single layer dvd. So there isn't much wiggle room left in the controls. What is the running time of your video?
You can try for a larger output size and burn onto a double layer disk. Or you can try a different encoder. AVStoDVD and FAVC do the same type of conversion as DVDFlick, but they can use a very high quality mpeg2 encoder called HCenc. You might get better results using one of those programs. Both are free to download and use. Make sure to set the output to the correct format, as AVStoDVD comes out of the box set to PAL standard. We use NTSC in the US.