I have the same problem as you. The emergency call button is too easy to activate and the power menu can be activated without unlocking the screen. Both are design faults. Some third party Android editions remedy the second problem, but not the first.
My ancient Nokia brick phones had a screen lock. They also had a bypass for emergency calls. But instead of automatically dialing 911/999, it brought you to the dialer screen. The only number you could enter was 911/999. Anything else would prompt for the unlock code.
I've seen people argue that dialing emergency services should be as simple as possible, that a catastrophic injury might make navigating menus and dialers difficult. For every scenario like that, how many times have emergency call centers run out of free operators, with a butt dialer or two being enough to push them to capacity?