Amen. Jesus already traded his life, so it would be double dipping if we tried to think about trading our own salvation. Besides, if someone decides not to put their faith in Christ, it's that person's choice. I want to spend forever with God and they don't; why would I be in a place I don't want to be forever to put them in a place they chose not to be as well? Even for the dearest people in my life I wouldn't trade my salvation. And I wont ever need to since Jesus' death is sufficient for everyone. Not fruitful to ponder it honestlyI took this question to be: would you give up salvation if it meant witnessing to another? Putting aside the idea if whether such a things was possible (I don't think it is), my answer is 'No'. Not even for my kids whom I would sacrifice anything else for. Jesus said you needed to put Him first, before all others. Our relationship with Him is what He wants us to focus on and I don't think we win brownie points by saying we'd trade our salvation for someone else.
Fortunately we aren't ever going to be asked something like that, so it's a moot point, but I suppose it is worth thinking about if your salvation really is the most important thing in your life or not.