It is not especially advisable to ride an amalgam. To someone unaccustomed to being around wetware military constructs, prolonged contact with one tends to elicit feelings of unrest, and even depression. Touching one with bare skin often evokes unpleasant childhood memories and sudden, stabbing fear—people have likened the tactile sensation to everything from the feel of cold bathroom tiles, to holding a mass of live hornets.
Repeated exposure seems to diminish the effects considerably, but even battle hardened magicians accustomed to being around demonic constructs are strongly discouraged from doing so for lengthy periods of time. An amalgam may also unconsciously try to integrate a hapless rider into their anatomical structure if they have been on them long enough.
Lafayette is considered to have a bit of a death wish when it comes to this.