У вашего броузера проблема в совместимости с HTML5
In my quest to make the T1+T2 SUP viable, I had to search for a way to "quickly" solo 6 man HP HoE SC's. This is what I ended up with.
Chipping the head health down a bit right to 8-9% (ideal) or 10+% (not ideal but workable). Then finish him off with 2 (ideal) or 3 (non-ideal) headshots with the alt fire from the HSG.
Doable due to the changes to the way SC targets you slower so you can just outbackdash him. After that you just need to get used to where his head hitbox is going to be and which attacks have the slowest recovery time allowing you to get the "perfect" headshots in.
Done on a dedicated server.