The Doctor proceeded to scan the membrane from this side, arching an eyebrow at the readings. The bubble was fascinating but worrying at the same time. He wondered if passing through it weakened its ability to hold together properly. Although, if it was a partially permeable membrane, surely something like osmosis would be a factor.
"K9 why don't you go and get a sample hmm?" John said to the robot dog next to him and Rose.
"Yes, Master," K9 said before trundling off to do so.
"Rose... what's wrong?" John asked softly after a moment.