May be a translation could help you figure it out, if you’re a native English speaker ? I’ll give this a shot :

We’re still in the front line, risking our lives.

We’re seated at a table, drinking wine.

Here, "à" is just used to convey a sense of simultaneity to both actions, whereas "pour" would mean that we’re seated at a table in order to drink wine (in which case I’d recommend an AA meeting asap).

A late answer here, but it occurs to me that this construction, i.e. "à + infinitive", crops up when the present participle is unavailable, after verbs evoking states rather than actions.
In other words, you might say, "il a réussi à venir, en risquant sa vie", but not "à risquer…" or "nous écoutons le concert, en buvant du vin" but not "à boire…".
The "à + infinitive" sequences seem to provide a development, or a gloss of the main clause to the left.