Classical musicians seem to have an unshakeable poise that gives the illusion of immunity to everyday circumstances. But that myth bites the dust hard in the second episode of the Philadelphia Orchestra’s digital season that streams starting 8 p.m. Thursday (and will be on demand for 72 hours).

In pre-performance interviews, star piano soloist Emanuel Ax, now 71, candidly talks about wishing he could’ve been a COVID first responder but more realistically hopes that he’ll live to play more Mozart concertos with the Philadelphia Orchestra. The 30-ish composer Jessica Hunt discusses how connecting with Beethoven’s hearing disability allowed her new piece, titled Climb, to be deeply informed by her own chronic illness, dysautonomia, a nervous system dysfunction. Principal bassoonist Daniel Matsukawa goes into moving detail about the inner life of Brahms as heard in his Serenade No. 2 that occupies the program’s second half.

The concert itself sounds and looks lovely, this one shot partly during daytime with a sense of the nature that’s all around the semi-outdoor Mann Center for the Performing Arts where these concerts are recorded on the expansive, socially-distanced stage (and with the hum of the city heard in the distance). But the tone set by the interviews and the extremely alert performances underscore how the increasingly imperiled medium of classical music concerts expresses elemental life-and-death matters.

Ax’s performance of Mozart’s Piano Concerto No. 14 K. 449 is a model of musical honesty. He uses an expanse of slightly-slower-than-usual tempos to remind you that nothing in this externally charming concerto is purely decorative, and that all elements of the music serve multiple simultaneous functions.

Yes, the keyboard trills are pretty, for example, but Ax also uses them to heighten the propulsion of the music. He give the musical content a strong sense of character without ever disturbing the music’s graceful contour or sparkling services. This is Mozart that had nothing to hide, but also nothing to confess, leaving its musical doors wide open for listeners to bring their own inner lives and emotional responses.

Serenades by major composers are getting lots of mileage in scaled-back symphonic concerts everywhere, sometimes frustratingly so since some of them are middle-weight, uneven works. But middling Brahms — as in his Serenade No. 2  — is still pretty crunchy stuff.

Though some conductors emphasize the village-band folksiness of the wind writing, music director Yannick Nézet-Séguin treats the entire piece as a work unlimited by its cultural antecedents, and the performance shows that even without violins in its orchestration, the piece can be elevated by the Philadelphia sound.

Hunt’s Climb, a Philadelphia Orchestra commission and world premiere, is a short, highly eventful piece full of edgy, irregular rhythms that are abruptly interrupted, making room for rhetorically powerful solos for concertmaster David Kim and concluding with an enigmatic moment for clarinetist Ricardo Morales that suggests hope is mainly provisional.

Though Beethoven was the philosophical starting point, 20th-century British composer William Walton is a closer musical ancestor, with a lot of sequential tension building that very much allows you to, as Hunt put it in her interview, “Walk a mile in my dysautonomia shoes.” The piece asks for empathy, not pity, and needs to be much, much longer.

Tickets are $15 and are available at philorch.org.