Well, given the cost of purchasing After Effects I would advise the following.

Do as you suggested in Photoshop. It will not take as long as you thought, believe me. You are going to yank a guy off his feet. I suspect you will have at most about a second of footage to edit. This will be 25/30 frames to touch up. If you're used to Photoshop then a quick clone brush would only tgake an hour to do this lot.

Once you cut to the dude lying on the floor for any close-up shot you would have removed the wire so no editing needed there.

All you then have to worry about is not to shoot any footage of him waiting to be shot wioth the wire hanging around behind him. Arrange your shoot so he stands on his own, cut to the person with the gun, cut back for the getting shot scens where your actor is now harnessed up.

It shouldn't be too hard to reduce the amount of work needed by planning the shoot.

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