Yeah, this was a laugh-out-loud strip alright. Both in Claire's reaction and Bubbles' reaction.
Claire is such a romantic and Elliott is such a sweet personality that, naturally, the thought of such a person having a crush on Clinton would put her deep into "SQUEE!" territory. It probably says a lot about Bubbles and how difficult she, like many combat veterans, finds it putting battlefield reactions behind them, that she reacts automatically to a sudden noise. I don't think that a single conscious thought passed through her mind between her snapping into active mode in panel 2 and coming to a halt in Marten and Claire's bedroom. If she owned a gun, she'd probably be waving it around too!
Fixing that door is not going to be easy; even if the hinges are undamaged, Bubbles smashed the lock receiver out of the frame so the whole door-frame will need to be replaced. Trust me, I work for a company that operates youth hostels; I have extensive experience with busted doors. Poor Marten is going to have a difficult time explaining this one to the landlord!
I do hope that Claire remembers her bitter lesson and doesn't try to 'help' Clinton and Elliott. Oh, who am I kidding? A shipper like her will be trying to get the 'real story' at any moment that she's not doing anything urgent!
Final thought that occurs to me: Marten and Claire sleep in the buff. Now, if that's the way they do it then that's the way they do it. However, for some reason I can't help visualise Veronica smirking at them in a knowing way.