Jo, Zette & Jocko: The Secret Ray - did the scientist kill himself?

I'm referring to the most sinister and disturbing of Herge's work in my opinion.

I know it seems clear he did commit suicide by smashing the glass, but then who set off the explosion moments later?

I haven't read that story for years but wasn't the explosion (or rather implosion) a result of the different pressure outside the underwater building and all the water rushing in due to the broken glass?

I didn't think of that, but I always thought there was a suggestion that the professor didn't die from what Mr Legrand said...

edit: - sorry about the bump