To get your tablet out of "Safe Mode" try the following.
Restart your device by holding the power button, then tap Power off.
Tap OK to confirm.
Power the device on.
Your tablet should now be out of safe mode.
If the device is still in safe mode use one of the following methods.
To uninstall the last application you installed:
Go into the "Apps" menu and tap on "Settings".
Next tap on the app you installed just before the problem started and then tap on "Uninstall".
Restart your device.
NOTE: This one is a last resort option. You would want to back up any personal data (addressbook, photos, vids, etc.,) before attempting this, as all would be cleared off your phone.
As last resort, you can perform a factory data reset:
Go...