Drilling screw in 91 sl panel removal

[tswafford]

I am having a door lock problem after a new lock actuator was installed by a local shop. I am attemping to remove the panel to check the vacuum line. When I removed the front pocket screw I found a very large machine screw that was very hard to remove. The back screw was stripped, ie, it would turn but not unscrew out or in. I tried a lever to push the panel against the screw to no avail. This back screw is buried in the panel plastic about 1.5 in.
Then I attempted to drill out the screw head. I have used bosch titanium drills and a home depot colbalt drill. These bit are not able to drill through this head. I have a little progress but it is not progressing.
Any ideas on how to procede? Thanks in advance for any ideas.