[gpm]

In this case, per the article, "shelter" meant "shelter in a capsule capable of returning to earth and put on the spacesuits that you wear during return to earth".

I.e. leaving the actual ISS structure entirely.

[bmelton]

I would guess they're worried about breaking something, but thanks for the clarification (and apologies for not having RTFA)

[lazide]

Repairing a leak with an uncertain cause could be at high risk of catastrophic decompression if it was caused by certain types of corrosion or stress.