Rudi Opitz, the principal test pilot on the Me163 program who survived to be picked up in Operation Paperclip and worked in the U.S. aerospace industry for many years. He also worked in the Me110 test program before WWII. He was a noted soaring pilot as well and passed away in 2010 at the age of 99. Here's a pic from his Me163 testing days, note the "flight data recorder" strapped to his head. https://www.soaringmuseum.org/hof_more.php?id=78
Yep. The oxidizer was mostly hydrogen peroxide, and the fuel lines ran through the cockpit, resulting in a few, quite literally, "melted" pilots. It was a nasty little machine.
The fuel was so volatile and toxic that the oxidizer and fuel trucks had to be kept completely separate. After fueling, the plane had to be decontaminated for any residual fuel outside of the plane's fuel tanks before the oxidizer truck could approach.
Putting that plane into the air probably did more damage to German industry and war capability than whatever bombers it shot down would have done.