It seems a lot of assumptions are being made by everyone - or context not being controlled for enough during responses - and it's too much effort to counter it all, some assumptions more or less reasonable than others; it's reasonable that they likely don't have an MRI, more likely they have x-ray and ultrasound - more likely reasonable to assume that based on the incident itself, what happened specifically, they can determine a reasonably safe course of action.

If there was an injury at work, and pain resulting from that, it's reasonable to assume that there was just an event that occurred to cause that injury/pain, right?

Basically missing from everyone's arguments are the specific contexts of different scenarios being argued around:

If someone hurts their hand and it visibly needs care, you send them to the hospital - that likely doesn't need to happen in an ambulance unless they're bleeding out and can't be stabilized.

If someone's just walking along or makes a twisting movement that that causes them immense back pain - and say, it wasn't from getting hit by any machinery moving quickly - then that sounds more like an inflammatory response the body does to stabilize an area that just had a nerve pinched than something more potentially devastating; a doctor should be able to based on the situation described by the person decide if they need to be mobilized and taken by ambulance or if taking a Lyft would be quicker getting them to full care. Likewise, that twisting movement should then be addressed to make sure their body can handle it or that their movement is proper for the task at end - that we could assume they're repeating often.

I've hurt my back before where I was walking like a hunchback 90 year old man, where I had to walk bent over a bit to stop the pain from getting worse; it was twisting from playing floor hockey after having just before done a hot yoga class, so my body was open and muscles weren't as tight/supportive - and it was only actually the next morning when the inflammatory reaction had kicked in/stabilized the area; I didn't go to the hospital, I did however call my chiropractor who I'd been seeing for other issues who could see and access me. She used heat and laser light to help reduce inflammation in the area (which helped), and told me to rest and not do yoga for a few weeks - and suggested anti-inflammatories if I wanted to take them. I half-jokingly pressed her to let me go after a week, to which I had a followup with her, went to the same hot yoga class 6 days later - and that heat, blood flow, stretching/strengthening - completely cleared whatever inflammation/pain process was happening in my spine and I felt 100% better afterward.

If someone was hit by machinery, say in the head, your decision making process will be different then if they're just walking and sprained an ankle. We can assume that if the on-site doctors are trained well then they're making good judgement calls based on the information presented to them, based on whatever diagnostics they may have available; the fail-safe to this is however why there are organizations like OSHA, to hopefully make sure good/acceptable decisions are being made.

My biggest concern in all of this would every doctor's ability for critical thinking, including having strong situational awareness, however that would come with proper/adequate training - and that would be required for any on-site doctors, ambulance attendants, or doctors working at hospitals.

EDIT: Just to point out - there was also an assumption made that my response was talking about this doctor's response/behaviour if he was at the Tesla facility and in the context of a worker coming to them on-site at Tesla, when in fact the context was never set and I wasn't specifically referencing what diagnostic tools they may have at Tesla.

No, I'm not saying that in all cases pain can be attributed to something observable. There are different causes that can be from an immediate larger injury, to repetitive stress injuries - and likewise not excluding holistic influences, whether it being a source of pressure on nerves in the spine or even a diet that causes high inflammation in the body; different medications can certainly cause people problems too, whether increasing the sensation of pain and/or allowing them to cope until a minor injury becomes worse.

The person commenting above made a general statement that was actually wrong - they made a false assertion, saying that because it can't be objectively found (in the foot) it must mean the doctor doesn't believe it's there - when in fact the doctor simply said it can't be proven: that doesn't state whether the doctor believes the pain is there, nor what action for care would happen or recommend. If there's pain in the foot and nothing shows up on ultrasound, X-Ray (or motion X-ray), MRI - then you'd need to move up the body to see where else pain may be coming from - the spine being a stronger possibility as pain can radiate down. Likewise, as you said, many people with chronic pain can attest to there not perhaps being a physical cause - and we know that emotional pain/stress can manifest into the physical body; and because of plant medicines, higher use of psychedelics and their ability to help people reconnect and process repressed/suppressed emotions, people often report physical pain (arthritic type pain on all their joints, "heart pains", etc) going away often after one or a few Ayahuasca ceremonies, etc.

From my own experience doctors and the medical system have a really terrible understanding of pain, perception of pain. Luckily regenerative medicine (with stem cells et al) is giving options for people in pain to "experiment" - and with great success in many cases, assuming the process/protocol followed is from a research/evidence-based process (e.g. you're not getting treated by someone who only kind of knows what they are doing).