Minecraft PE world on fire/killing in creative (old)

I remember a few years ago, me and my friend where playing MC creative. We joined my world (this was around before you could break bedrock in mc pe, and you had a very limited selection of items example: No buckets, Wearing armor, etc. in creative ) but then we where using blocks to move around lava. Then a part of my world (a grass field) had smoke particles coming from it, so my friend stepped on it and died (this was before you could die in creative, and if you left the game in survival your inv. get's deleted) when he died he lost all his stuff from his creative inv. I remember after we dug into into a hill and made a base.