She tries to grip it with both flippers and turn it, but she finds her new body awkward to move and her skin slides off. She reorients herself, swirling around the water as she does. She lines herself up, opens her mouth, and swims forward then clamps her mouth down on the handle between her tusks, then twists her body trying to turn the handle and pull back, but slips again.
Frustrated, she swims back into the operations room to look for anything that might help her turn or break the handle before she just tries to ram it open.
She finds and bites onto some books—they might provide her some better purchase on the handle. She swims back to the door and maneuvers one book face on side of the handle, holding it in place with one flipper, then places the other book face on the other side. Then she presses her flippers together as hard as she can, moving one up and one down, trying to get the handle to turn.
Rolls
Deterity ? - (1d20-1)
(8) - 1 = 7
Investigation (Subtract 3 if Perception fits better) - (1d20+7)
(19) + 7 = 26
Strength? - (1d20+2)
(15) + 2 = 17