It's kind of slow for an ambulance, though... :/
Same speed as the Harvester Ant, though, and I figure something like this is probably going to be used in rough or otherwise impassable terrain, where slow speed and stability is more important, and VTOL options can't reach due to weather or lack of safe LZ.
Looking at the ambulance units in Tech Readout Vehicle Annex, they all seem to have standardized on 6 seats per unit of paramedic equipment, each used to treat and transport one patient plus medical staff. Since this is a 'Mech I figured they may need more insulation and padding and thought of the cargo bays like infantry bays, with one "squad"/ton to represent the same. That gives us the ability to move 4 patients at once, andlooking at Tech Manual, foot infantry bays (not compartments) are 5 tons for 28 troops, or 178.6 kg/person. Two tons works out to roughly 11 people.
One option then would be to cut the environmental sealing and put in a bigger position engine. One extra ton gets my 4/6 and two gets me 5/8 while keeping a fuel cell. Going with fusion would be half that extra mass, introduces the idea of unlimited electricity and heat, but also strapping them into a walking fusion reactor. On top of that, environmental sealing seems handy, but it would require either that or lower passenger capacity - extra engine weight has to come from somewhere.
Of course, I could always go fusion, stick an Urbie's Leenex 60 in there, and gain back a half ton for more stuff. I could even cut 2 tons of cargo and some paramedic equipment for a lift hoist or salvage arm or maybe even manipulators to use for rescues.
