how far to push a patient?

I am currently doing Gerontology at RPH WPC and am treating a patient who was diagnosed with cellulitis primarily in the right leg who was coming along well until 2 weeks ago where symptoms started flaring up again and has made very little progress ever since then.
This patient has come from hostel which requires her to ambulate independently with a WZF at least 40 metres in order to walk from her room to the dining room and to be discharged to return to hostel. Through subjective findings as well as according to my supervisor, patient has become depressed since the second episode of deterioration and is very unmotivated + lack of self confidence ++ and has reduced in compliance with exercises. She is currently able to ambulate 25m WZF with supervision limited by Reduced confidence according to my supervisor, reduced exercise tolerance, general deconditioned especially weakness in (R) LL (reduced strength and endurance of hip extensor, knee extensor primarily) and reduced balance (poor saving response and righting reaction).
It was my second visit of this patient in the afternoon of Friday 25th May and after a few repetitions of bed exercises and some strengthening exercises in standing, Patient obs was stable and rested for 15 minutes and I decided to continue her walking program aiming for the dining room which was 35 m from the gym with a chair set up in her room which is located halfway of the journey. Patient's gait was looking better with less trunk flexion and better feet clearance compared to first visit and I constantly provided motivation and compliments verbally which worked fantastically and pursuaded the patient to continue to head towards the dining room which was about 15m further without taking a rest in between.
At the end of the session,as patient was positioning herself to sit on the chair in the dining room, she suddenly collapsed, but fortunately Curtin graduates usually tend to be safe with patient handling (thanks to the neuro team) I remained close to the patient and was able to support the patient on time and lowered her down slowly onto the ground. I had a quick screen of her pulse and obs which was stable and called for help. Eventually patient was positioned safely back into the chair with 3 ppl transfer and AIMS was completed.
Fortunately and surprisingly enough that this patient became more motivated post session after seeing the distance that she managed despite the incident that occured in the end but I can imagine how very possible to put off some other patients with the same incident. Therefore, I do understand it is often important to motivate patients in order to push them to their limits in order to gain the most out of exercises especially when we are trying to boost their exercise tolerance with a pt with nil cardiovascular complications. My question will be how much to push them onwards where in this case patient's response will be unreliable where she was constantly demanding to sit down after every 5m of walking or so?