I agree with Kent. I had two true tests of the strength of the plans seat belt construction. First was when I was doing the testing of the supercharging system on my E Racer in 2000. Was on a extended downwind for rw33 and on my turn to final, 1/2 mile out at 400 ft the engine quit. would not restart and I did a gear up landing in a bean field about 1/8 mile short of rw33. The groung was soft from two days of rain and when the AC was at 2ft, the right dug into the raising terrain and exploded(blew of the right wing ) flew 300 feet behind the AC. It felt like I hit a solid rock. Point being, the seat belt anchors were not compromized in any way. Second, When I had the inflight fire incident last year, I put the AC on the runway hard and fast, 200 mph, colapsed the left main grae and slid down the runway 1500 ft, still did not compromize the seat belt anchors. That is until the fire consumed the AC. My opinion, move on, that little air bubble will make no difference in the safety of the seatbelt system.
Jack
E Racer Extreme