This skill use the first two "status-sensitive key slots" (in game keybinds), not the keys you have mapped for left and right movement. When you activate mirror warp that toolbar opens (same one that controls your glider, ship, vehicles, etc) and effectively disables any other keys you have mapped to that toolbar.

So, be aware. If you have that toolbar mapped to the same keys as your basic shortcut bar, the first ten mapped hotkeys on that shortcut bar will be disabled (you cannot use those abilities) until you teleport left or right or the timer runs out (about 5 seconds). That also means if you have the 10-ability passive "teleport discipline" and it procs for an auto-reset of mirror warp, you are forced to teleport again before you can use any of your attack abilities.

If you are going to use this skill you may want to consider mapping "status-sensitive key slots" to keys not used in your basic shortcut bar.