How can I access my photos/videos from my HTC Sensation XL default on 'charge only' and with unresponsive touch screen?
You can simply use an app like WiFi File Transfer as explained in this answer. You can use a USB OTG cable and connect a mouse to use your phone for your data recovery process.

You may have to hurry as the water that is already inside the device can harm the hardware in your device. Keep the device turned off and remove battery. Try to give it a little bit of sunlight. do not expose it to direct strong sunlight.