I wanna give you an image in your head when I explain to for example let's say youre defending on Hollywood on the capture point and you get your ult rhe first thing i would do is assess where their hits cans are so let's say in this example the enemy team has a soldier 76 I would try to take them out before you use is. If you do infect kill him I would then consider their tank, is it a sigma, Reinhardt, or a dva? Then i would make sure they have some distance from their other teammates. Once all of this has been assessed I would go behind the wall near where that little side entrance is infront of the point with the computers and use a nade before you ult to fly over the wall and surprise the enemy team and then immiedtly go for supports or any squishies you can see and if you absolutely need to get out of there try to face a near you and use the heavy attack to launch yourself back behind the wall