Oi! I'd do it!

In Classic style Professor Brian Cox turned in a great mind-warp moment, it is my pleasure to uncover the workings...

Scene 1 - Brian enters and walks through the cave system explaining:
"...Although this cave is a death-trap for us [humans]... look at these fish!"
Distracted by cave-dwelling fish in a 'death-trap', all the while the moments are ticking by and as long as Brian's still smiling we know he is not suffering the effects of...

Scene 2 - The noxious atmosphere:
"...the concentration of gas (hydrogen sulphide) was strong enough to set off my alarm".
He walked deeper into the cave with the alarm growing ever louder.

Scientist Prof. Brian Cox does not matabolise Hydrogen Sulphide but mere Oxygen like the rest of us scientists or not! The black-ish humour abounds, m'dears.

BBC Secrets of The Solar System presented by Prof. Brian Cox, sundays. Although the programme is more like Earth Science meets Astrophysics, hence the cave environment on Earth possibly having a planetary replicer on Io, which is a satalite (moon) of Jupiter.