Quote

When you suffer [strain], place that [strain] on this card instead of your hero sheet. Discard this card when it has 4 or more [strain]. During your activation, an adjacent hero may claim this card.

What does "4 or more" mean? Standard English would dictate that you get to chose whether you discard it when there are 4 strain tokens on it, or you could discard it when there are more tokens on it. Take your pick.

It's obviously not that, but I'd love to get some interpretations of what you can and cannot do with this card based on the wording.

I believe the accepted interpretation allows you to use a 2 strain ability when you have 3 strain on the card. Both strain would go on the card, and it would then get discarded with 5 strain on it.

The above is correct. When you suffer 2 (or more) strain at once, they are suffered simultaneously, thus they all get put on Artificial Stimulants .