With the other side vulnerable, your LHO (South) opens one of a suit, your partner (West) doubles (takeout), RHO (North) passes. You (East) have KQJ97 of the bid suit and a bunch of small side suit cards (in a 5-3-3-2 distribution). That is to say, you have no side suit strength whatsoever.
Your suit holding is stronger than opener's likely ATxxx. Still, I can see a scenario where the opening bidder might make the one level contract (but without overtricks) for a score of 160 (50 part score, 60 for doubled contract, 50 for the double itself), meaning -160 to you. With them vulnerable, you will be +200 if they go down one, doubled.
With two suits of xxx (all x's 7 or lower), you fear that the penalty for bidding one of them opposite Hxxx (H is an ace or king honor) and going down will be greater than -160. This is particularly true if the bid suit is spades (or even hearts if your doubleton is in spades), and you need to go to the two level to bid a suit with xxx.
How do the risks and rewards of passing for penalty balance out? Given that they are vulnerable, how might your vulnerability figure in this calculation?