If the steps to get you out of "Safe Mode" don't work, then I would have to wonder if there is something wrong with the volume button on your device. If there is, then there is no way to stay out of "Safe Mode" until you get the button fixed.
I am also including, just in case you missed something, the steps to get out of it below. Can't hurt to try (as long as it isn't a button issue).
To get out of Safe Mode, please try the following.
1. Touch and Hold the "Power" key.
2. Tap "Power Off".
3. Once the tablet is off, Touch and Hold the "Power" key again to restart.
The tablet should now be out of "Safe Mode".
If the "Safe Mode" is still running after you restart your tablet, I would then check to make sure your "Volume Down" button is not stuck. Check to see if it has anything stuck in it as well, dust, etc. Anything like this can cause the tablet to go into, and get stuck in, "Safe Mode".
If that doesn't work try this...
Use the "Status Bar" to turn off "Safe Mode'. Pull down (swipe) the "Status Bar" of your phone. Now tap the "Safe Mode" button. This should turn "Safe Mode" off. Now your tablet will automatically restart, so that it boots up out of "Safe Mode".
And lastly...
If you want to get rid of/disable "Safe Mode".
1. First turn off the tablet.
2. Next press and hold "Power" until you see the manufacturers logo on the screen, then release the power button.
3. "Quickly" press "Volume Down" and hold it for few seconds until you see the message "Safe Mode: OFF" or something similar.
4. If you wanted re-enable it, simply repeat the steps above, and you should see "Safe mode: ON" rather than off.