Behind the scenes of VOY, either s3e14 "Alter Ego" or s6e8 "One Small Step" which are the 2 times Picardo directed.

kinda looks like he's wondering if anyone will smell that (purely logical) fart

Smelling it is only beginning of dealing it, not the end.

Ew, sounds like he really "ejected the warp core" if you know what I mean...

At a convention, Tim Russ told a few stories about being a real prankster on set, so maybe he just got rebuked by his coworker for messing up a shot

IIRC, Tim Russ was part of the ongoing 'gaseous anomaly' contest that some of the actors had going on...

Tim is giving the same look that my cat gives when I forget to feed her and she's deciding if she's hungry enough to eat my face yet.

The Doctor was not in his starfleet uniform

The Doctor was the one who refused to split Tuvix with his "do no harm" bullshit. That's how he earned his ire.

Spending even one extra second as Tuvix must've been unbearable.