How can you see through the floor? Simple question, simple answer.
You can see out of the window yes but the relative position of an aircraft passing above you when you're inverted is BELOW you. You can not see through the floor.
Unless you're BSing and they actually weren't that close you might have been able to see them at a longer range as the relative angle between you would be smaller. But then if they weren't that close would there be any need for such a ridiculous manuever?
Instead of rolling and pulling why not just pull? Or push?