Ctting out a moving character from the background of a clip and superimposing on top of another clip

OMG I'm grateful to you all. Now I know where I messed up earlier. Thanks a bunch guys.

Fix: I used to select the mask(2)'s  mask path and all; instead I should have used the mask path under mask(1). I realized it was a personal error.

As Ann suggested, Rotoscoping in After Effects is the best option:

https://www.adobe.com/in/products/aftereffects/rotoscoping.html?ef_id=CjwKCAjw2ZaGBhBoEiwA8pfP_uYoQYsB8MIDaXpB4zsNBJB5ILern8t_zCI5hza0-mE0rHIcGMiKRBoC4BUQAvD_BwE:G:s&s_kwcid=AL!3085!3!453145736117!b!!g!!!1523460659!53763243570&gclid=CjwKCAjw2ZaGBhBoEiwA8pfP_uYoQYsB8MIDaXpB4zsNBJB5ILern8t_zCI5hza0-mE0rHIcGMiKRBoC4BUQAvD_BwE

sometimes we ( people in general ) imagine what we want and want to make it happen but it simply can't be done with our resources and expertise, etc. Let's say you wanna fly off the roof of your house but everytime you jump off the roof flapping your arms like a bird you end up going to the hospital... 

my suggestion is to think of alternative ways to accomplish close to what you want and you can then solve the problem.

For example, I had a script in mind that required shooting a brownstone in NYC. I hunted around MN. twin cities for a location ( exterior shot ) and found out there is nothing here like that. At first I thought I was dead in the water, but then realized I could use a neighbors condo with text to ' pretend' it was basically the same thing.... namely, THE LOCATION.

in your case you might be able to rethink the edit and do a PIP type thing to show the character you want running around, but also show the other game footage where it kinda makes sense ???

don't get stuck on imagination or techical stuff...keep thinking around the box you built yourself with the initial idea.

good luck